Acne, also known as ''acne vulgaris'', is a long-term
A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of t ...
that occurs when dead skin cells
and oil from the skin
The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction betw ...
Typical features of the condition include blackheads or whiteheads
A pimple is a kind of comedo that results from excess sebum and dead skin cells getting trapped in the pores of the skin. In its aggravated state, it may evolve into a pustule or papules. Pimples can be treated by acne medications, antibiotics, ...
s, oily skin, and possible scar
It primarily affects skin with a relatively high number of
An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturat ...
, including the face, upper part of the chest, and back.
The resulting appearance can lead to
Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat w ...
Self-esteem is confidence in one's own worth or abilities. Self-esteem encompasses beliefs about oneself (for example, "I am loved", "I am worthy") as well as emotional states, such as triumph, despair, pride, and shame. Smith and Mackie (2007) d ...
, and, in extreme cases, depression
or thoughts of suicide
Susceptibility to acne is primarily genetic in 80% of cases.
The roles of diet and
Tobacco smoking is the practice of burning tobacco and ingesting the resulting smoke. The smoke may be inhaled, as is done with cigarettes, or simply released from the mouth, as is generally done with pipes and cigars. The practice is believ ...
in the condition are unclear, and neither
Cleanliness is both the state of being clean and free from germs, dirt, trash, or waste, and the habit of achieving and maintaining that state. Cleanliness is often achieved through cleaning. Culturally, cleanliness is usually a good quality, ...
nor exposure to sunlight appear to play a part.
In both sex
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required ...
An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This inc ...
s appear to be part of the underlying mechanism, by causing increased production of sebum
Another common factor is the excessive growth of the bacterium ''
''Cutibacterium acnes'' (formerly ''Propionibacterium acnes'') is the relatively slow-growing, typically aerotolerant anaerobic, gram-positive bacterium (rod) linked to the skin condition of acne; it can also cause chronic blepharitis and endop ...
'', which is present on the skin.
Treatments for acne are available, including lifestyle changes, medications, and medical procedures. Eating fewer simple carbohydrates
Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double ...
may minimize the condition.
Treatments applied directly to the affected skin
, such as azelaic acid
, benzoyl peroxide
Salicylic acid is an organic compound with the formula HOC6H4CO2H. A colorless, bitter-tasting solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone, and has been listed by the EPA Toxic Subst ...
, are commonly used.
[ ] Antibiotics
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ... and retinoids
The retinoids are a class of chemical compounds that are vitamers of vitamin A or are chemically related to it. Retinoids have found use in medicine where they regulate epithelial cell growth.
Retinoids have many important functions throughout ... are available in formulations that are applied to the skin and taken by mouth for the treatment of acne. [ However, resistance to antibiotics may develop as a result of antibiotic therapy.] Several types of birth control pills Oral contraceptives, abbreviated OCPs, also known as birth control pills, are medications taken by mouth for the purpose of birth control.
Two types of female oral contraceptive pill, taken once per day, are widely available:
* The combi ... help prevent acne in women. [ Medical professionals typically reserve ] isotretinoin
Isotretinoin, also known as 13-''cis''-retinoic acid and sold under the brand name Accutane among others, is a medication primarily used to treat severe acne. It is also used to prevent certain skin cancers (squamous-cell carcinoma), and in th ... pills for severe acne, due to greater potential side effects. Early and aggressive treatment of acne is advocated by some in the medical community to decrease the overall long-term impact on individuals. [
In 2015, acne affected approximately 633million people globally, making it the eighth-most common disease worldwide.] Acne commonly occurs in adolescence
Adolescence () is a transitional stage of physical and psychological development that generally occurs during the period from puberty to adulthood (typically corresponding to the age of majority). Adolescence is usually associated with t ... and affects an estimated 80–90% of teenagers in the Western world
The Western world, also known as the West, primarily refers to the various nations and states in the regions of Europe, North America, and Oceania.. Some rural societies report lower rates of acne than industrialized ones. Children and adults may also be affected before and after puberty. Although acne becomes less common in adulthood, it persists in nearly half of affected people into their twenties and thirties, and a smaller group continues to have difficulties in their forties. [
The severity of acne vulgaris (Gr. ἀκµή, "point" + L. ''vulgaris'', "common") can be classified as mild, moderate, or severe to determine an appropriate treatment regimen.
There is no universally accepted scale for grading acne severity. The presence of clogged skin follicles (known as comedones) limited to the face with occasional inflammatory lesions defines mild acne. [ Moderate severity acne is said to occur when a higher number of inflammatory ] papule
A papule is a small, well-defined bump in the skin. It may have a rounded, pointed or flat top, and may have a dip. It can appear with a stalk, be thread-like or look warty. It can be soft or firm and its surface may be rough or smooth. Some h ...s and pustule
A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of thi ...s occur on the face, compared to mild cases of acne, and appear on the trunk of the body. [ Severe acne is said to occur when nodules (the painful 'bumps' lying under the skin) are the characteristic facial lesions, and involvement of the trunk is extensive.] [
Large nodules were previously called cysts. The term ''nodulocystic'' has been used in the medical literature to describe severe cases of inflammatory acne.] True cysts are rare in those with acne, and the term ''severe nodular acne'' is now the preferred terminology. [
''Acne inversa'' (L. invertō, "upside-down") and ''acne rosacea'' (rosa, "rose-colored" + -āceus, "forming") are not forms of acne and are alternate names that respectively refer to the skin conditions hidradenitis suppurativa (HS) and ] rosacea
Rosacea is a long-term skin condition that typically affects the face. It results in redness, pimples, swelling, and small and superficial dilated blood vessels. Often, the nose, cheeks, forehead, and chin are most involved. A red, enlarge .... Although HS shares certain overlapping features with acne vulgaris, such as a tendency to clog skin follicles with skin cell debris, the condition otherwise lacks the hallmark features of acne and is therefore considered a distinct skin disorder.
Signs and symptoms
Typical features of acne include increased secretion of oily sebum by the skin, microcomedones, comedones, papules, nodules (large papules), pustules, and often results in scarring.
[ The appearance of acne varies with skin color. It may result in psychological and social problems.] [
Acne scars are caused by
Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ... within the dermis
The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided ... and are estimated to affect 95% of people with acne vulgaris. Abnormal healing and dermal inflammation create the scar. Scarring is most likely to take place with severe acne but may occur with any form of acne vulgaris. Acne scars are classified based on whether the abnormal healing response following dermal inflammation leads to excess collagen
Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whol ... deposition or loss at the site of the acne lesion.
Atrophic acne scars have lost collagen from the healing response and are the most common type of acne scar (accounting for approximately 75% of all acne scars). Ice-pick scars, boxcar scars, and rolling scars are subtypes of atrophic acne scars. Boxcar scars are round or ovoid indented scars with sharp borders and vary in size from 1.5–4 mm across. [ Ice-pick scars are narrow (less than 2 mm across), deep scars that extend into the dermis.] [ Rolling scars are broader than ice-pick and boxcar scars (4–5 mm across) and have a wave-like pattern of depth in the skin.] [
Hypertrophic scars are uncommon and are characterized by increased collagen content after the abnormal healing response.] [ They are described as firm and raised from the skin.] Hypertrophic scars remain within the original margins of the wound, whereas keloid scars can form scar tissue outside of these borders. [ Keloid scars from acne occur more often in men and people with darker skin, and usually occur on the trunk of the body.] [
In November 2021 a study was published exposing the consensus of twenty-four renowned international plastic surgeons and dermatologists about the most effective energy-based devices for the treatment of acne scars.
After an inflamed nodular acne lesion resolves, it is common for the skin to darken in that area, which is known as postinflammatory hyperpigmentation (PIH). The inflammation stimulates specialized pigment-producing skin cells (known as
Melanocytes are melanin-producing neural crest-derived cells located in the bottom layer (the stratum basale) of the skin's epidermis, the middle layer of the eye (the uvea),
the inner ear,
vaginal epithelium, meninges,
...s) to produce more melanin
Melanin (; from el, μέλας, melas, black, dark) is a broad term for a group of natural pigments found in most organisms. Eumelanin is produced through a multistage chemical process known as melanogenesis, where the oxidation of the am ... pigment, which leads to the skin's darkened appearance. PIH occurs more frequently in people with darker skin color. [ Pigmented scar is a common term used for PIH, but is misleading as it suggests the color change is permanent. Often, PIH can be prevented by avoiding any aggravation of the nodule and can fade with time. However, untreated PIH can last for months, years, or even be permanent if deeper layers of skin are affected.] Even minimal skin exposure to the sun's ultraviolet rays can sustain hyperpigmentation. Daily use of SPF 15 or higher sunscreen
Sunscreen, also known as sunblock or sun cream, is a photoprotective topical product for the skin that mainly absorbs, or to a much lesser extent reflects, some of the sun's ultraviolet (UV) radiation and thus helps protect against sunburn an ... can minimize such a risk.
Risk factors for the development of acne, other than genetics, have not been conclusively identified. Possible secondary contributors include hormones, infections, diet, and stress. Studies investigating the impact of smoking on the incidence and severity of acne have been inconclusive.
Sunlight and cleanliness are not associated with acne.
Acne appears to be highly
Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic infor ...; genetics explain 81% of the variation in the population. Studies performed in affected twins and first-degree relatives further demonstrate the strongly inherited nature of acne. Acne susceptibility is likely due to the influence of multiple genes, as the disease does not follow a classic (Mendelian) inheritance pattern. These gene candidates include certain variations in tumor necrosis factor-alpha (TNF-alpha), IL-1 alpha
Interleukin-1 alpha (IL-1 alpha) also known as hematopoietin 1 is a cytokine of the interleukin 1 family that in humans is encoded by the ''IL1A'' gene. In general, Interleukin 1 is responsible for the production of inflammation, as well as the ..., and CYP1A1 genes, among others. The 308 G/A single nucleotide polymorphism variation in the gene for TNF is associated with an increased risk for acne. Acne can be a feature of rare genetic disorders such as Apert's syndrome. Severe acne may be associated with XYY syndrome
XYY syndrome, also known as Jacobs syndrome, is an aneuploid genetic condition in which a male has an extra Y chromosome. There are usually few symptoms. These may include being taller than average, acne, and an increased risk of learning disa ....
Hormonal activity, such as occurs during menstrual cycles and
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy ..., may contribute to the formation of acne. During puberty, an increase in sex hormones called androgen
An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This inc ...s causes the skin follicle glands to grow larger and make more oily sebum. The androgen hormones testosterone
Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristi ..., dihydrotestosterone (DHT), and dehydroepiandrosterone (DHEA) are all linked to acne. High levels of growth hormone (GH) and insulin-like growth factor 1 (IGF-1) are also associated with worsened acne. Both androgens and IGF-1 seem to be essential for acne to occur, as acne does not develop in individuals with complete androgen insensitivity syndrome (CAIS) or Laron syndrome (insensitivity to GH, resulting in very low IGF-1 levels).
Medical conditions that commonly cause a high-androgen state, such as polycystic ovary syndrome, congenital adrenal hyperplasia
Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders characterized by impaired cortisol synthesis. It results from the deficiency of one of the five enzymes required for the synthesis of cortisol in the adrenal cortex. ..., and androgen-secreting tumors, can cause acne in affected individuals. Conversely, people who lack androgenic hormones or are insensitive to the effects of androgens rarely have acne. [ Pregnancy can increase androgen levels, and consequently, oily sebum synthesis.] Acne can be a side effect of testosterone replacement therapy or anabolic steroid
Anabolic steroids, also known more properly as anabolic–androgenic steroids (AAS), are steroidal androgens that include natural androgens like testosterone as well as synthetic androgens that are structurally related and have similar effects ... use. Over-the-counter bodybuilding
Bodybuilding is the use of progressive resistance exercise to control and develop one's muscles (muscle building) by muscle hypertrophy for aesthetic purposes. It is distinct from similar activities such as powerlifting because it focuse ... and dietary supplement
A dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in orde ...s often contain illegally added anabolic steroids.
The anaerobic bacterial species ''
''Cutibacterium acnes'' (formerly ''Propionibacterium acnes'') is the relatively slow-growing, typically aerotolerant anaerobic, gram-positive bacterium (rod) linked to the skin condition of acne; it can also cause chronic blepharitis and endop ...'' (formerly ''Propionibacterium acnes'') contributes to the development of acne, but its exact role is not well understood. [ There are specific sub-strains of ''C. acnes'' associated with normal skin and others with moderate or severe inflammatory acne.] [ It is unclear whether these undesirable strains evolve on-site or are acquired, or possibly both depending on the person. These strains have the capability of changing, perpetuating, or adapting to the abnormal cycle of inflammation, oil production, and inadequate sloughing of dead skin cells from acne pores. Infection with the parasitic mite '' Demodex'' is associated with the development of acne.] It is unclear whether eradication of the mite improves acne. [
High- glycemic-load diets have been found to have different degrees of effect on acne severity.
Multiple randomized controlled trial
A randomized controlled trial (or randomized control trial; RCT) is a form of scientific experiment used to control factors not under direct experimental control. Examples of RCTs are clinical trials that compare the effects of drugs, surgical t ...s and nonrandomized studies have found a lower-glycemic-load diet to be effective in reducing acne. [ There is weak observational evidence suggesting that dairy milk consumption is positively associated with a higher frequency and severity of acne.] Milk contains whey protein and hormones such as bovine IGF-1 and precursors of dihydrotestosterone. [ Studies suggest these components promote the effects of insulin and IGF-1 and thereby increase the production of androgen hormones, sebum, and promote the formation of comedones.] [ Available evidence does not support a link between eating chocolate or salt and acne severity.] [ Few studies have examined the relationship between ] obesity
Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ... and acne. Vitamin B12 may trigger skin outbreaks similar to acne (acneiform eruptions), or worsen existing acne when taken in doses exceeding the recommended daily intake.
There are few high-quality studies to demonstrate that stress causes or worsens acne.
Despite being controversial, some research indicates that increased acne severity is associated with high stress levels in certain contexts, such as hormonal changes seen in premenstrual syndrome
Premenstrual syndrome (PMS) refers to emotional and physical symptoms that regularly occur in the one to two weeks before the start of each menstrual period. Symptoms resolve around the time menstrual bleeding begins. Different women experi ....
Some individuals experience severe intensification of their acne when they are exposed to hot humid climates; this is due to bacteria and fungus thriving in warm, moist environments. This climate induced acne exacerbation has been termed tropical acne.
Mechanical obstruction of skin follicles with helmets or chinstraps can worsen pre-existing acne.
However, when acne is caused by mechanical obstruction it is not considered a form of acne vulgaris when being very technical. It would be an other acneiform eruption known as Acne mechanica.
Several medications can also worsen pre-existing acne; this condition is the acne medicamentosa
form of acne. Examples of such medications include lithium
Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid e ..., hydantoin
Hydantoin, or glycolylurea, is a heterocyclic organic compound with the formula CH2C(O)NHC(O)NH. It is a colorless solid that arises from the reaction of glycolic acid and urea. It is an oxidized derivative of imidazolidine. In a more general sen ..., isoniazid
Isoniazid, also known as isonicotinic acid hydrazide (INH), is an antibiotic used for the treatment of tuberculosis. For active tuberculosis it is often used together with rifampicin, pyrazinamide, and either streptomycin or ethambutol. For ..., glucocorticoids, iodides
An iodide ion is the ion I−. Compounds with iodine in formal oxidation state −1 are called iodides. In everyday life, iodide is most commonly encountered as a component of iodized salt, which many governments mandate. Worldwide, iodine ..., bromides, and testosterone
Testosterone is the primary sex hormone and anabolic steroid in males. In humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristi .... When acne medicamentosa is specifically caused by anabolic–androgenic steroids it can simply be referred to as steroid acne
Steroid acne is an adverse reaction to corticosteroids, and presents as small, firm follicular papules on the forehead, cheeks, and chest.James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. ....
Genetically susceptible individuals can get acne breakouts as a result of polymorphous light eruption; a condition triggered by sunlight and artificial UV light exposure. This form of acne is called Acne aestivalis and it's specifically caused by intense UVA light exposure. Affected individuals usually experience seasonal acne breakouts on their upper arms, shoulder girdle, back, and chest. The breakouts typically occur one-to-three days after they've been exposed to intese UVA radiation. Unlike other forms of acne the condition spares the face; this could possibly be a result of the pathogenesis of polymorphous light eruption, in which areas of the skin that are ''newly'' exposed to intense ultraviolet radiation are affected. Since faces are typically left uncovered at all stages of life there's little-to-no likelihood for an eruption to appear there. Studies show that both polymorphous light eruption outbreaks and the acne aestivalis breakout response can be prevented by topical antioxidants combined with the application of a broad spectrum sunscreen.
Acne vulgaris is a chronic skin disease of the
A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest numbe ... and develops due to blockages in the skin's hair follicle
The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction betw ...s. These blockages occur as a result of the following four abnormal processes: increased oily sebum production (influenced by androgen
An androgen (from Greek ''andr-'', the stem of the word meaning "man") is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This inc ...s), excessive deposition of the protein keratin leading to comedo formation, colonization of the follicle by ''Cutibacterium acnes'' (''C. acnes'') bacteria, and the local release of pro-inflammatory chemicals in the skin.
The earliest pathologic change is the formation of a plug (a microcomedone), which is driven primarily by excessive growth, reproduction, and accumulation of skin cells in the hair follicle. [ In healthy skin, the skin cells that have died come up to the surface and exit the pore of the hair follicle.] In people with acne, the increased production of oily sebum causes the dead skin cells to stick together. The accumulation of dead skin cell debris and oily sebum blocks the pore of the hair follicle, thus forming the microcomedone. The ''C. acnes'' biofilm
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular p ... within the hair follicle worsens this process. [ If the microcomedone is superficial within the hair follicle, the skin pigment ] melanin
Melanin (; from el, μέλας, melas, black, dark) is a broad term for a group of natural pigments found in most organisms. Eumelanin is produced through a multistage chemical process known as melanogenesis, where the oxidation of the am ... is exposed to air, resulting in its oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ... and dark appearance (known as a blackhead or open comedo). [ In contrast, if the microcomedone occurs deep within the hair follicle, this causes the formation of a whitehead (known as a closed comedo).]
The main hormonal driver of oily sebum production in the skin is dihydrotestosterone. [ Another androgenic hormone responsible for increased sebaceous gland activity is DHEA-S. The ] adrenal gland
The adrenal glands (also known as suprarenal glands) are endocrine glands that produce a variety of hormones including adrenaline and the steroids aldosterone and cortisol. They are found above the kidneys. Each gland has an outer cortex wh ...s secrete higher amounts of DHEA-S during adrenarche
Adrenarche is an early stage in sexual maturation that happens in some higher primates and in humans, typically peaks at around 20 years of age, and is involved in the development of pubic hair, body odor, skin oiliness, axillary hair, sexual ... (a stage of puberty
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy ...), and this leads to an increase in sebum production. In a sebum-rich skin environment, the naturally occurring and largely commensal
Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ... skin bacterium ''C. acnes'' readily grows and can cause inflammation
Inflammation (from la, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants, and is a protective response involving immune cells, blood vessels, and molec ... within and around the follicle due to activation of the innate immune system
The innate, or nonspecific, immune system is one of the two main immunity strategies (the other being the adaptive immune system) in vertebrates. The innate immune system is an older evolutionary defense strategy, relatively speaking, and is the .... ''C. acnes'' triggers skin inflammation in acne by increasing the production of several pro-inflammatory chemical signals (such as IL-1α, IL-8, TNF-α, and LTB4); IL-1α is essential to comedo formation.
''C. acnes ability to bind and activate a class of immune system
The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splint ... receptors known as toll-like receptor
Toll-like receptors (TLRs) are a class of proteins that play a key role in the innate immune system. They are single-pass membrane-spanning receptors usually expressed on sentinel cells such as macrophages and dendritic cells, that recognize ...s (TLRs), especially TLR2
Toll-like receptor 2 also known as TLR2 is a protein that in humans is encoded by the ''TLR2'' gene. TLR2 has also been designated as CD282 ( cluster of differentiation 282). TLR2 is one of the toll-like receptors and plays a role in the immune ... and TLR4
Toll-like receptor 4 is a protein that in humans is encoded by the ''TLR4'' gene. TLR4 is a transmembrane protein, member of the toll-like receptor family, which belongs to the pattern recognition receptor (PRR) family. Its activation leads to an ..., is a core mechanism of acne-related skin inflammation. Activation of TLR2 and TLR4 by ''C. acnes'' leads to increased secretion of IL-1α, IL-8, and TNF-α. [ The release of these inflammatory signals attracts various immune cells to the hair follicle, including ] neutrophil
Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying i ...s, macrophage
Macrophages (abbreviated as M φ, MΦ or MP) ( el, large eaters, from Greek ''μακρός'' (') = large, ''φαγεῖν'' (') = to eat) are a type of white blood cell of the immune system that engulfs and digests pathogens, such as cancer ce ...s, and Th1 cells. [ IL-1α stimulates increased skin cell activity and reproduction, which, in turn, fuels comedo development.] [ Furthermore, sebaceous gland cells produce more ] antimicrobial peptides
Antimicrobial peptides (AMPs), also called host defence peptides (HDPs) are part of the innate immune response found among all classes of life. Fundamental differences exist between prokaryotic and eukaryotic cells that may represent targets for ..., such as HBD1 and HBD2, in response to the binding of TLR2 and TLR4. [
''C. acnes'' also provokes skin inflammation by altering the fatty composition of oily sebum.] [ Oxidation of the ] lipid
Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids includ ... squalene
Squalene is an organic compound. It is a triterpenoid with the formula C30H50. It is a colourless oil, although impure samples appear yellow. It was originally obtained from shark liver oil (hence its name, as '' Squalus'' is a genus of sharks) ... by ''C. acnes'' is of particular importance. Squalene oxidation activates NF-κB
Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a protein complex that controls transcription of DNA, cytokine production and cell survival. NF-κB is found in almost all animal cell types and is involved in cellula ... (a protein complex) and consequently increases IL-1α levels. [ Additionally, squalene oxidation increases 5-lipoxygenase enzyme activity, which catalyzes the conversion of ] arachidonic acid
Arachidonic acid (AA, sometimes ARA) is a polyunsaturated omega-6 fatty acid 20:4(ω-6), or 20:4(5,8,11,14). It is structurally related to the saturated arachidic acid found in cupuaçu butter. Its name derives from the New Latin word ''arach ... to leukotriene B4 (LTB4). [ LTB4 promotes skin inflammation by acting on the ] peroxisome proliferator-activated receptor alpha
Peroxisome proliferator-activated receptor alpha (PPAR-α), also known as NR1C1 (nuclear receptor subfamily 1, group C, member 1), is a nuclear receptor protein functioning as a transcription factor that in humans is encoded by the ''PPARA'' gen ... (PPARα) protein. [ PPARα increases the activity of activator protein 1 (AP-1) and NF-κB, thereby leading to the recruitment of inflammatory ] T cell
A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell re ...s. [ ''C. acnes ability to convert sebum triglycerides to pro-inflammatory free fatty acids via secretion of the enzyme ] lipase
Lipase ( ) is a family of enzymes that catalyzes the hydrolysis of fats. Some lipases display broad substrate scope including esters of cholesterol, phospholipids, and of lipid-soluble vitamins and sphingomyelinases; however, these are usually t ... further explains its inflammatory properties. [ These free fatty acids spur increased production of cathelicidin, HBD1, and HBD2, thus leading to further inflammation.] [
This inflammatory cascade typically leads to the formation of inflammatory acne lesions, including ] papule
A papule is a small, well-defined bump in the skin. It may have a rounded, pointed or flat top, and may have a dip. It can appear with a stalk, be thread-like or look warty. It can be soft or firm and its surface may be rough or smooth. Some h ...s, infected pustule
A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of thi ...s, or nodules. [ If the inflammatory reaction is severe, the follicle can break into the deeper layers of the dermis and ] subcutaneous tissue
The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and m ... and cause the formation of deep nodules. The involvement of AP-1 in the aforementioned inflammatory cascade activates matrix metalloproteinases, which contribute to local tissue destruction and scar formation. [
Along with the bacteria ''C. acnes'', the bacterial species ''Staphylococcus epidermidis'' (''S. epidermidis'') also takes a part in the physiopathology of acne vulgaris. The proliferation of ''S. epidermidis'' with ''C. acnes'' causes the formation of ] biofilms
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular po ..., which blocks the hair follicles and pores, creating an anaerobic environment under the skin. This enables for increased growth of both ''C. acnes'' and ''S. epidermidis'' under the skin. The proliferation of ''C. acnes'' causes the formation of biofilms
A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular po ... and a biofilm matrix, making it even harder to treat the acne.
Acne vulgaris is diagnosed based on a medical professional's clinical judgment.
The evaluation of a person with suspected acne should include taking a detailed medical history about a family history of acne, a review of medications taken, signs or symptoms of excessive production of androgen hormones, cortisol, and growth hormone. Comedones (blackheads and whiteheads) must be present to diagnose acne. In their absence, an appearance similar to that of acne would suggest a different skin disorder. Microcomedones (the precursor to blackheads and whiteheads) are not visible to the naked eye when inspecting the skin and require a microscope to be seen. Many features may indicate that a person's acne vulgaris is sensitive to hormonal influences. Historical and physical clues that may suggest hormone-sensitive acne include onset between ages 20 and 30; worsening the week before a woman's period; acne lesions predominantly over the jawline and chin; and inflammatory/nodular acne lesions. [
Several scales exist to grade the severity of acne vulgaris, but disagreement persists about the ideal one for diagnostic use.] Cook's acne grading scale uses photographs to grade severity from 0 to 8, with higher numbers representing more severe acne. This scale was the first to use a standardized photographic protocol to assess acne severity; since its creation in 1979, the scale has undergone several revisions. [ The Leeds acne grading technique counts acne lesions on the face, back, and chest and categorizes them as inflammatory or non-inflammatory. Leeds scores range from 0 (least severe) to 10 (most severe) though modified scales have a maximum score of 12.] [ The Pillsbury acne grading scale classifies the severity of the acne from grade 1 (least severe) to grade 4 (most severe).]
Many skin conditions can mimic acne vulgaris, and these are collectively known as acneiform eruptions.
Such conditions include angiofibromas, epidermal cysts, flat warts, folliculitis, keratosis pilaris, milia, perioral dermatitis, and rosacea
Rosacea is a long-term skin condition that typically affects the face. It results in redness, pimples, swelling, and small and superficial dilated blood vessels. Often, the nose, cheeks, forehead, and chin are most involved. A red, enlarge ..., among others. [ Age is one factor that may help distinguish between these disorders. Skin disorders such as perioral dermatitis and keratosis pilaris can appear similar to acne but tend to occur more frequently in childhood. Rosacea tends to occur more frequently in older adults.] [ Facial redness triggered by heat or the consumption of alcohol or spicy food is also more suggestive of rosacea.] The presence of comedones helps health professionals differentiate acne from skin disorders that are similar in appearance. Chloracne and occupational acne due to exposure to certain chemicals & industrial compounds, may look very similar to acne vulgaris.
Many different treatments exist for acne. These include alpha hydroxy acid, anti-androgen medications, antibiotics, antiseborrheic medications, azelaic acid, benzoyl peroxide, hormonal treatments,
Keratolytic () therapy is a type of medical treatment to remove warts, calluses and other lesions in which the epidermis produces excess skin. In this therapy, acidic topical medicines, such as Whitfield's ointment or Jessner's solution, are ap ... soaps, nicotinamide
Niacinamide or Nicotinamide (NAM) is a form of vitamin B3 found in food and used as a dietary supplement and medication. As a supplement, it is used by mouth to prevent and treat pellagra (niacin deficiency). While nicotinic acid (niacin) may ..., retinoids
The retinoids are a class of chemical compounds that are vitamers of vitamin A or are chemically related to it. Retinoids have found use in medicine where they regulate epithelial cell growth.
Retinoids have many important functions throughout ..., and salicylic acid
Salicylic acid is an organic compound with the formula HOC6H4CO2H. A colorless, bitter-tasting solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone, and has been listed by the EPA Toxic Subst .... [ Acne treatments work in at least four different ways, including the following: reducing inflammation, hormonal manipulation, killing ''C. acnes'', and normalizing skin cell shedding and sebum production in the pore to prevent blockage.] Typical treatments include topical therapies such as antibiotics, benzoyl peroxide, and retinoids, and systemic therapies, including antibiotics, hormonal agents, and oral retinoids.
Recommended therapies for first-line use in acne vulgaris treatment include topical retinoids, benzoyl peroxide, and topical or oral antibiotics. Procedures such as light therapy and laser therapy are not first-line treatments and typically have only an add on role due to their high cost and limited evidence. [ Blue light therapy is of unclear benefit. Medications for acne target the early stages of comedo formation and are generally ineffective for visible skin lesions; acne generally improves between eight and twelve weeks after starting therapy.]
People often view acne as a short-term condition, some expecting it to disappear after puberty. This misconception can lead to depending on self-management or problems with long-term adherence to treatment. Communicating the long-term nature of the condition and better access to reliable information about acne can help people know what to expect from treatments.
In general, it is recommended that people with acne do not wash affected skin more than twice daily.
The application of a fragrance-free moisturizer to sensitive and acne-prone skin may reduce irritation. Skin irritation from acne medications typically peaks at two weeks after onset of use and tends to improve with continued use. Dermatologists recommend using cosmetic products that specifically say non-comedogenic, oil-free, and won't clog pores.
Acne vulgaris patients, even those with oily skin, should moisturize in order to support the skin's moisture barrier since skin barrier dysfunction may contribute to acne. Moisturizers, especially ceramide-containing moisturizers, as an adjunct therapy are particularly helpful for the dry skin and irritation that commonly results from topical acne treatment. Studies show that ceramide-containing moisturizers are important for optimal skin care; they enhance acne therapy adherence and complement existing acne therapies. In a study where acne patients used 1.2% clindamycin phosphate / 2.5% benzoyl peroxide gel in the morning and applied a micronized 0.05% tretinoin gel in the evening the overwhelming majority of patients experienced no cutaneous adverse events throughout the study. It was concluded that using ceramide cleanser and ceramide moisturizing cream caused the favorable tolerability, did not interfere with the treatment efficacy, and improved adherence to the regimen. The importance of preserving the acidic mantle and its barrier functions is widely accepted in the scientific community. Thus, maintaining a pH in the range 4.5 - 5.5 is essential in order to keep the skin surface in its optimal, healthy conditions.
Causality (also referred to as causation, or cause and effect) is influence by which one event, process, state, or object (''a'' ''cause'') contributes to the production of another event, process, state, or object (an ''effect'') where the cau ... relationship is rarely observed with diet/nutrition and dermatologic conditions. Rather, associations — some of them compelling — have been found between diet and outcomes including disease severity and the number of conditions experienced by a patient. Evidence is emerging in support of medical nutrition therapy as a way of reducing the severity and incidence of dermatologic diseases, including acne. Researchers observed a link between high glycemic index diets and acne. Dermatologists also recommend a diet low in simple sugars as a method of improving acne. [ As of 2014, the available evidence is insufficient to use milk restriction for this purpose.] [
Benzoyl peroxide (BPO) is a first-line treatment for mild and moderate acne due to its effectiveness and mild side-effects (mainly skin irritation). In the skin follicle, benzoyl peroxide kills ''C. acnes'' by oxidizing its proteins through the formation of oxygen free radicals and
Benzoic acid is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, .... These free radicals likely interfere with the bacterium's metabolism and ability to make proteins. Additionally, benzoyl peroxide is mildly effective at breaking down comedones and inhibiting inflammation. Combination products use benzoyl peroxide with a topical antibiotic or retinoid, such as benzoyl peroxide/clindamycin and benzoyl peroxide/adapalene, respectively. [ Topical benzoyl peroxide is effective at treating acne.
Side effects include increased skin photosensitivity, dryness, redness, and occasional peeling.] Sunscreen use is often advised during treatment, to prevent sunburn
Sunburn is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and animals include: red or reddish skin that is .... Lower concentrations of benzoyl peroxide are just as effective as higher concentrations in treating acne but are associated with fewer side effects. Unlike antibiotics, benzoyl peroxide does not appear to generate bacterial antibiotic resistance. [
The retinoids are a class of chemical compounds that are vitamers of vitamin A or are chemically related to it. Retinoids have found use in medicine where they regulate epithelial cell growth.
Retinoids have many important functions throughout ... are medications that reduce inflammation, normalize the follicle cell life cycle, and reduce sebum production. They are structurally related to vitamin A
Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably .... Studies show dermatologists and primary care doctors underprescribe them for acne. The retinoids appear to influence the cell life cycle in the follicle lining. This helps prevent the accumulation of skin cells within the hair follicle that can create a blockage. They are a first-line acne treatment, [ especially for people with dark-colored skin. Retinoids are known to lead to faster improvement of postinflammatory hyperpigmentation.]
Topical retinoids include adapalene, retinol, retinaldehyde, isotretinoin
Isotretinoin, also known as 13-''cis''-retinoic acid and sold under the brand name Accutane among others, is a medication primarily used to treat severe acne. It is also used to prevent certain skin cancers (squamous-cell carcinoma), and in th ..., tazarotene, trifarotene, and tretinoin. They often cause an initial flare-up of acne and facial flushing and can cause significant skin irritation. Generally speaking, retinoids increase the skin's sensitivity to sunlight and are therefore recommended for use at night. [ Tretinoin is the least expensive of the topical retinoids and is the most irritating to the skin, whereas adapalene is the least irritating but costs significantly more.] Most formulations of tretinoin are incompatible for use with benzoyl peroxide. Tazarotene is the most effective and expensive topical retinoid but is usually not as well tolerated. [ In 2019 a tazarotene lotion formulation, marketed to be a less irritating option, was approved by the FDA. Retinol is a form of vitamin A that has similar but milder effects and is present in many over-the-counter moisturizers and other topical products.
Isotretinoin is an oral retinoid that is very effective for severe nodular acne, and moderate acne that is stubborn to other treatments.] [ One to two months of use is typically adequate to see improvement. Acne often resolves completely or is much milder after a 4–6 month course of oral isotretinoin.] [ After a single round of treatment, about 80% of people report an improvement, with more than 50% reporting complete remission.] [ About 20% of people require a second course, but 80% of those report improvement, resulting in a cumulative 96% efficacy rate.] [
There are concerns that isotretinoin is linked to adverse effects, like depression, ] suicidality
Suicide is the act of intentionally causing one's own death. Mental disorders (including depression, bipolar disorder, schizophrenia, personality disorders, anxiety disorders), physical disorders (such as chronic fatigue syndrome), and ..., and anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, .... There is no clear evidence to support some of these claims. Isotretinoin has been found in some studies to be superior to antibiotics or placebo in reducing acne lesions. However, a 2018 review comparing inflammatory lesions after treatment with antibiotics or isotretinoin found no difference. The frequency of adverse events was about twice as high with isotretinoin use, although these were mostly dryness-related events. No increased risk of suicide or depression was conclusively found.
Medical authorities strictly regulate isotretinoin use in women of childbearing age due to its known harmful effects in pregnancy. For such a woman to be considered a candidate for isotretinoin, she must have a confirmed negative pregnancy test
A pregnancy test is used to determine whether a female is pregnant or not. The two primary methods are testing for the female pregnancy hormone (human chorionic gonadotropin (hCG)) in blood or urine using a pregnancy test kit, and scanning with ... and use an effective form of birth control
Birth control, also known as contraception, anticonception, and fertility control, is the use of methods or devices to prevent unwanted pregnancy. Birth control has been used since ancient times, but effective and safe methods of birth contr .... In 2008, the United States started the iPLEDGE program to prevent isotretinoin use during pregnancy. iPledge requires the woman to have two negative pregnancy tests and to use two types of birth control for at least one month before isotretinoin therapy begins and one month afterward. The effectiveness of the iPledge program is controversial due to continued instances of contraception nonadherence.
People may apply antibiotics to the skin or take them orally to treat acne. They work by killing ''C. acnes'' and reducing inflammation.
Although multiple guidelines call for healthcare providers to reduce the rates of prescribed oral antibiotics, many providers do not follow this guidance. Oral antibiotics remain the most commonly prescribed systemic therapy for acne. Widespread broad-spectrum antibiotic
A broad- spectrum antibiotic is an antibiotic that acts on the two major bacterial groups, Gram-positive and Gram-negative, or any antibiotic that acts against a wide range of disease-causing bacteria. These medications are used when a bacterial i ... overuse for acne has led to higher rates of antibiotic-resistant ''C. acnes'' strains worldwide, especially to the commonly used tetracycline
Tetracycline, sold under various brand names, is an oral antibiotic in the tetracyclines family of medications, used to treat a number of infections, including acne, cholera, brucellosis, plague, malaria, and syphilis.
Common side effect ... (e.g., doxycycline) and macrolide antibiotics (e.g., topical erythromycin). Therefore, dermatologists prefer antibiotics as part of combination therapy and not for use alone.
Commonly used antibiotics, either applied to the skin or taken orally, include clindamycin
Clindamycin is an antibiotic medication used for the treatment of a number of bacterial infections, including osteomyelitis (bone) or joint infections, pelvic inflammatory disease, strep throat, pneumonia, acute otitis media (middle ear infe ..., erythromycin, metronidazole, sulfacetamide, and tetracyclines (e.g., doxycycline or minocycline
Minocycline, sold under the brand name Minocin among others, is a tetracycline antibiotic medication used to treat a number of bacterial infections such as pneumonia. It is generally less preferred than the tetracycline doxycycline. It is also ...). [ Doxycycline 40 milligrams daily (low-dose) appears to have similar efficacy to 100 milligrams daily and has fewer gastrointestinal side effects.] However, low-dose doxycycline is not FDA-approved for the treatment of acne. Antibiotics applied to the skin are typically used for mild to moderately severe acne. [ Oral antibiotics are generally more effective than topical antibiotics and produce faster resolution of inflammatory acne lesions than topical applications.] [ Topical and oral antibiotics are not recommended for use together.]
Oral antibiotics are recommended for no longer than three months as antibiotic courses exceeding this duration are associated with the development of antibiotic resistance and show no clear benefit over shorter durations. If long-term oral antibiotics beyond three months are used, then it is recommended that benzoyl peroxide or a retinoid be used at the same time to limit the risk of ''C. acnes'' developing antibiotic resistance.
The antibiotic dapsone
Dapsone, also known as 4,4'-sulfonyldianiline (SDA) or diaminodiphenyl sulfone (DDS), is an antibiotic commonly used in combination with rifampicin and clofazimine for the treatment of leprosy. It is a second-line medication for the treatment an ... is effective against inflammatory acne when applied to the skin. It is generally not a first-line choice due to its higher cost and a lack of clear superiority over other antibiotics. Topical dapsone is sometimes a preferred therapy in women or for people with sensitive or darker-toned skin. It is not recommended for use with benzoyl peroxide due to the risk of causing yellow-orange skin discoloration with this combination. Minocycline is an effective acne treatment, but it is not a first-line antibiotic due to a lack of evidence that it is better than other treatments, and concerns about its safety compared to other tetracyclines.
Sarecycline is the most recent oral antibiotic developed specifically for the treatment of acne, and is FDA-approved for the treatment of moderate to severe inflammatory acne in patients nine years of age and older. It is a narrow-spectrum tetracycline antibiotic that exhibits the necessary antibacterial activity against pathogens related to acne vulgaris and a low propensity for inducing antibiotic resistance. In clinical trials, sarecycline demonstrated clinical efficacy in reducing inflammatory acne lesions as early as three weeks and reduced truncal (back and chest) acne.
In women, the use of
combined birth control pill
The combined oral contraceptive pill (COCP), often referred to as the birth control pill or colloquially as "the pill", is a type of birth control that is designed to be taken orally by women. The pill contains two important hormones: progesti ...s can improve acne. These medications contain an estrogen
Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ... and a progestin
A progestogen, also referred to as a progestagen, gestagen, or gestogen, is a type of medication which produces effects similar to those of the natural female sex hormone progesterone in the body. A progestin is a '' synthetic'' progestogen. P .... They work by decreasing the production of androgen hormones by the ovaries and by decreasing the free and hence biologically active fractions of androgens, resulting in lowered skin production of sebum and consequently reduce acne severity. First-generation progestins such as norethindrone and norgestrel
Norgestrel, sold under the brand name Ovral among others, is a progestin medication which is used in birth control pills and in menopausal hormone therapy. It is available both in combination with an estrogen and alone. It is taken by mouth.
... have androgenic properties and may worsen acne. Although oral estrogens decrease IGF-1 levels in some situations, which could theoretically improve acne symptoms, combined birth control pills do not appear to affect IGF-1 levels in fertile women. Cyproterone acetate
Cyproterone acetate (CPA), sold alone under the brand name Androcur or with ethinylestradiol under the brand names Diane or Diane-35 among others, is an antiandrogen and progestin medication used in the treatment of androgen-dependent condition ...-containing birth control pills seem to decrease total and free IGF-1 levels. Combinations containing third- or fourth-generation progestin
A progestogen, also referred to as a progestagen, gestagen, or gestogen, is a type of medication which produces effects similar to those of the natural female sex hormone progesterone in the body. A progestin is a '' synthetic'' progestogen. P ...s, including desogestrel, dienogest, drospirenone
Drospirenone is a progestin and antiandrogen medication which is used in birth control pills to prevent pregnancy and in menopausal hormone therapy, among other uses. It is available both alone under the brand name Slynd and in combination ..., or norgestimate, as well as birth control pills containing cyproterone acetate or chlormadinone acetate, are preferred for women with acne due to their stronger antiandrogenic effects. Studies have shown a 40 to 70% reduction in acne lesions with combined birth control pills. A 2014 review found that oral antibiotics appear to be somewhat more effective than birth control pills at reducing the number of inflammatory acne lesions at three months. However, the two therapies are approximately equal in efficacy at six months for decreasing the number of inflammatory, non-inflammatory, and total acne lesions. [ The authors of the analysis suggested that birth control pills may be a preferred first-line acne treatment, over oral antibiotics, in certain women due to similar efficacy at six months and a lack of associated antibiotic resistance.] [ In contrast to combined birth control pills, progestogen-only birth control forms that contain androgenic progestins have been associated with worsened acne.]
Antiandrogens, also known as androgen antagonists or testosterone blockers, are a class of drugs that prevent androgens like testosterone and dihydrotestosterone (DHT) from mediating their biological effects in the body. They act by blocking t ...s such as cyproterone acetate and spironolactone
Spironolactone, sold under the brand name Aldactone among others, is a medication that is primarily used to treat fluid build-up due to heart failure, liver scarring, or kidney disease. It is also used in the treatment of high blood pressur ... can successfully treat acne, especially in women with signs of excessive androgen production, such as increased hairiness or skin production of sebum, or scalp hair loss. [ Spironolactone is an effective treatment for acne in adult women.] Unlike combined birth control pills, it is not approved by the United States Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ... for this purpose. Spironolactone is an aldosterone antagonist and is a useful acne treatment due to its ability to additionally block the androgen receptor
The androgen receptor (AR), also known as NR3C4 (nuclear receptor subfamily 3, group C, member 4), is a type of nuclear receptor that is activated by binding any of the androgenic hormones, including testosterone and dihydrotestosterone in the ... at higher doses. Alone or in combination with a birth control pill, spironolactone has shown a 33 to 85% reduction in acne lesions in women. The effectiveness of spironolactone for acne appears to be dose-dependent. High-dose cyproterone acetate alone reportedly decreases acne symptoms in women by 75 to 90% within three months. It is usually combined with an estrogen to avoid menstrual irregularities and estrogen deficiency. The medication appears to be effective in the treatment of acne in males, with one study finding that a high dosage reduced inflammatory acne lesions by 73%. However, spironolactone and cyproterone acetate's side effects in males, such as gynecomastia, sexual dysfunction
Sexual dysfunction is difficulty experienced by an individual or partners during any stage of normal sexual activity, including physical pleasure, desire, preference, arousal, or orgasm. The World Health Organization defines sexual dysfunction a ..., and decreased bone mineral density, generally make their use for male acne impractical.
Pregnant and lactating women should not receive antiandrogens for their acne due to a possibility of birth disorders such as hypospadias
Hypospadias is a common variation in fetal development of the penis in which the urethra does not open from its usual location in the head of the penis. It is the second-most common birth abnormality of the male reproductive system, affecting abo ... and feminization of male babies. [ Women who are sexually active and who can or may become pregnant should use an effective method of contraception to prevent pregnancy while taking an antiandrogen.] Antiandrogens are often combined with birth control pills for this reason, which can result in additive efficacy. The FDA added a black-box warning to spironolactone about possible tumor
A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ... risks based on preclinical research with very high doses (>100-fold clinical doses) and cautioned that unnecessary use of the medication should be avoided. However, several large epidemiological studies subsequently found no greater risk of tumors in association with spironolactone in humans. Conversely, strong associations of cyproterone acetate with certain brain tumor
A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and second ...s have been discovered and its use has been restricted. The brain tumor risk with cyproterone acetate is due to its strong progestogenic actions and is not related to antiandrogenic activity nor shared by other antiandrogens.
Flutamide, a pure antagonist
An antagonist is a character in a story who is presented as the chief foe of the protagonist.
The English word antagonist comes from the Greek ἀνταγωνιστής – ''antagonistēs'', "opponent, competitor, villain, enemy, ri ... of the androgen receptor, is effective in treating acne in women. It appears to reduce acne symptoms by 80 to 90% even at low doses, with several studies showing complete acne clearance. In one study, flutamide decreased acne scores by 80% within three months, whereas spironolactone decreased symptoms by only 40% in the same period. In a large long-term study, 97% of women reported satisfaction with the control of their acne with flutamide. Although effective, flutamide has a risk of serious liver toxicity, and cases of death in women taking even low doses of the medication to treat androgen-dependent skin and hair conditions have occurred. As such, the use of flutamide for acne has become increasingly limited, and it has been argued that continued use of flutamide for such purposes is unethical. Bicalutamide, a pure androgen receptor antagonist with the same mechanism as flutamide and with comparable or superior antiandrogenic efficacy but with a far lower risk of liver toxicity, is an alternative option to flutamide in the treatment of androgen-dependent skin and hair conditions in women.
Clascoterone is a topical
A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of classes ... antiandrogen that has demonstrated effectiveness in the treatment of acne in both males and females and was approved for clinical use for this indication in August 2020. It has shown no systemic absorption or associated antiandrogenic side effects. In a small direct head-to-head comparison, clascoterone showed greater effectiveness than topical isotretinoin. 5α-Reductase inhibitors such as finasteride
Finasteride, sold under the brand names Proscar and Propecia among others, is a medication used to treat hair loss and benign prostatic hyperplasia (BPH) in men. It can also be used to treat excessive hair growth in women and as a part of ho ... and dutasteride may be useful for the treatment of acne in both males and females but have not been adequately evaluated for this purpose. Moreover, 5α-reductase inhibitors have a strong potential for producing birth defects in male babies and this limits their use in women. However, 5α-reductase inhibitors are frequently used to treat excessive facial/body hair in women and can be combined with birth control pills to prevent pregnancy. There is no evidence as of 2010 to support the use of cimetidine or ketoconazole
Ketoconazole, sold under the brand name Nizoral among others, is an antiandrogen and antifungal medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin infections such as tinea, cutaneous ca ... in the treatment of acne.
Hormonal treatments for acne such as combined birth control pills and antiandrogens may be considered first-line therapy for acne under many circumstances, including desired contraception, known or suspected hyperandrogenism, acne during adulthood, acne that flares premenstrually, and when symptoms of significant sebum production (seborrhea) are co-present. Hormone therapy is effective for acne both in women with hyperandrogenism and in women with normal androgen levels.
Azelaic acid is effective for mild to moderate acne when applied topically at a 15–20% concentration.
[ Treatment twice daily for six months is necessary, and is as effective as topical benzoyl peroxide 5%, isotretinoin 0.05%, and erythromycin 2%.] Azelaic acid is an effective acne treatment due to its ability to reduce skin cell accumulation in the follicle and its antibacterial and anti-inflammatory
Anti-inflammatory is the property of a substance or treatment that reduces inflammation or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs remedy pain by reducing inflammation as o ... properties. [ It has a slight skin-lightening effect due to its ability to inhibit melanin synthesis. Therefore, it is useful in treating individuals with acne who are also affected by post-inflammatory hyperpigmentation.] [ Azelaic acid may cause skin irritation. It is less effective and more expensive than retinoids.] [ Azelaic acid also led to worse treatment response when compared to benzoyl peroxide. When compared to tretinoin, azelaic acid makes little or no treatment response.
Salicylic acid is an organic compound with the formula HOC6H4CO2H. A colorless, bitter-tasting solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone, and has been listed by the EPA Toxic Subst ... is a topically applied beta-hydroxy acid that stops bacteria from reproducing and has keratolytic properties. It is less effective than retinoid therapy. [ Salicylic acid opens obstructed skin pores and promotes the shedding of epithelial skin cells.] Dry skin
Xeroderma, xerosis or xerosis cutis, or simply dry skin, is a skin condition characterized by excessively dry skin.
The medical term ''xeroderma'', meaning "dry skin", derives from modern Latin, ''xero-'' 'dry' + Greek ''derma'' 'skin'.
In most ... is the most commonly seen side effect with topical application, though darkening of the skin can occur in individuals with darker skin types. [
Topical and oral preparations of
Niacinamide or Nicotinamide (NAM) is a form of vitamin B3 found in food and used as a dietary supplement and medication. As a supplement, it is used by mouth to prevent and treat pellagra (niacin deficiency). While nicotinic acid (niacin) may ... (the amide
In organic chemistry, an amide, also known as an organic amide or a carboxamide, is a compound with the general formula , where R, R', and R″ represent organic groups or hydrogen atoms. The amide group is called a peptide bond when it i ... form of vitamin B3) are alternative medical treatments. Nicotinamide reportedly improves acne due to its anti-inflammatory properties, its ability to suppress sebum production, and its wound healing properties. [ Topical and oral preparations of zinc are suggested treatments for acne; evidence to support their use for this purpose is limited.] Zinc's capacities to reduce inflammation and sebum production as well as inhibit ''C. acnes'' growth are its proposed mechanisms for improving acne. [ ] Antihistamines
Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provid ... may improve symptoms among those already taking isotretinoin due to their anti-inflammatory properties and their ability to suppress sebum production.
Hydroquinone lightens the skin when applied topically by inhibiting tyrosinase
Tyrosinase is an oxidase that is the rate-limiting enzyme for controlling the production of melanin. The enzyme is mainly involved in two distinct reactions of melanin synthesis otherwise known as the Raper Mason pathway. Firstly, the hydroxyla ..., the enzyme responsible for converting the amino acid tyrosine
-Tyrosine or tyrosine (symbol Tyr or Y) or 4-hydroxyphenylalanine is one of the 20 standard amino acids that are used by cells to synthesize proteins. It is a non-essential amino acid with a polar side group. The word "tyrosine" is from the G ... to the skin pigment melanin
Melanin (; from el, μέλας, melas, black, dark) is a broad term for a group of natural pigments found in most organisms. Eumelanin is produced through a multistage chemical process known as melanogenesis, where the oxidation of the am ..., and is used to treat acne-associated post-inflammatory hyperpigmentation. By interfering with the production of melanin in the epidermis
The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water ..., hydroquinone leads to less hyperpigmentation as darkened skin cells are naturally shed over time. Improvement in skin hyperpigmentation is typically seen within six months when used twice daily. Hydroquinone is ineffective for hyperpigmentation affecting deeper layers of skin such as the dermis
The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided .... The use of a sunscreen
Sunscreen, also known as sunblock or sun cream, is a photoprotective topical product for the skin that mainly absorbs, or to a much lesser extent reflects, some of the sun's ultraviolet (UV) radiation and thus helps protect against sunburn an ... with SPF 15 or higher in the morning with reapplication every two hours is recommended when using hydroquinone. Its application only to affected areas lowers the risk of lightening the color of normal skin but can lead to a temporary ring of lightened skin around the hyperpigmented area. Hydroquinone is generally well-tolerated; side effects are typically mild (e.g., skin irritation) and occur with the use of a higher than the recommended 4% concentration. Most preparations contain the preservative sodium metabisulfite
Sodium metabisulfite or sodium pyrosulfite (IUPAC spelling; Br. E. sodium metabisulphite or sodium pyrosulphite) is an inorganic compound of chemical formula Na2S2O5. The substance is sometimes referred to as disodium metabisulfite. It is used a ..., which has been linked to rare cases of allergic reactions, including anaphylaxis
Anaphylaxis is a serious, potentially fatal allergic reaction and medical emergency that is rapid in onset and requires immediate medical attention regardless of use of emergency medication on site. It typically causes more than one of the foll ... and severe asthma
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, ... exacerbations in susceptible people. In extremely rare cases, the frequent and improper application of high-dose hydroquinone has been associated with a systemic condition known as exogenous ochronosis (skin discoloration and connective tissue
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tiss ... damage from the accumulation of homogentisic acid).
Combination therapy—using medications of different classes together, each with a different mechanism of action—has been demonstrated to be a more effective approach to acne treatment than monotherapy.
[ The use of topical benzoyl peroxide and ] antibiotic
An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...s together is more effective than antibiotics alone. Similarly, using a topical retinoid with an antibiotic clears acne lesions faster than the use of antibiotics alone. Frequently used combinations include the following: antibiotic and benzoyl peroxide, antibiotic and topical retinoid, or topical retinoid and benzoyl peroxide. [ Dermatologists generally prefer combining benzoyl peroxide with a retinoid over the combination of a topical antibiotic with a retinoid. Both regimens are effective, but benzoyl peroxide does not lead to antibiotic resistance.]
Although sebaceous gland activity in the skin increases during the late stages of pregnancy, pregnancy has not been reliably associated with worsened acne severity.
In general, topically applied medications are considered the first-line approach to acne treatment during pregnancy, as they have little systemic absorption and are therefore unlikely to harm a developing fetus
A fetus or foetus (; plural fetuses, feti, foetuses, or foeti) is the unborn offspring that develops from an animal embryo. Following embryonic development the fetal stage of development takes place. In human prenatal development, fetal devel .... Highly recommended therapies include topically applied benzoyl peroxide ( pregnancy category C) and azelaic acid (category B). Salicylic acid carries a category C safety rating due to higher systemic absorption (9–25%), and an association between the use of anti-inflammatory medications in the third trimester and adverse effects to the developing fetus including too little amniotic fluid in the uterus and early closure of the babies' ductus arteriosus
The ''ductus arteriosus'', also called the ''ductus Botalli'', named after the Italian physiologist Leonardo Botallo, is a blood vessel in the developing fetus connecting the trunk of the pulmonary artery to the proximal descending aorta. It a ... blood vessel. Prolonged use of salicylic acid over significant areas of the skin or under occlusive (sealed) dressings is not recommended as these methods increase systemic absorption and the potential for fetal harm. Tretinoin (category C) and adapalene (category C) are very poorly absorbed, but certain studies have suggested teratogenic effects in the first trimester. The data examining the association between maternal topical retinoid exposure in the first trimester of pregnancy and adverse pregnancy outcomes is limited. A systematic review of observational studies concluded that such exposure does not appear to increase the risk of major birth defects, miscarriages, stillbirths, premature births, or low birth weight. Similarly, in studies examining the effects of topical retinoids during pregnancy, fetal harm has not been seen in the second and third trimesters. Nevertheless, since rare harms from topical retinoids are not ruled out, they are not recommended for use during pregnancy due to persistent safety concerns. Retinoids contraindicated for use during pregnancy include the topical retinoid tazarotene, and oral retinoids isotretinoin and acitretin (all category X). Spironolactone is relatively contraindicated for use during pregnancy due to its antiandrogen effects. [ Finasteride is not recommended as it is highly teratogenic.] [
Topical antibiotics deemed safe during pregnancy include clindamycin, erythromycin, and metronidazole (all category B), due to negligible systemic absorption.] Nadifloxacin and dapsone (category C) are other topical antibiotics that may be used to treat acne in pregnant women but have received less study. No adverse fetal events have been reported from the topical use of dapsone. If retinoids are used there is a high risk of abnormalities occurring in the developing fetus; women of childbearing age are therefore required to use effective birth control
Birth control, also known as contraception, anticonception, and fertility control, is the use of methods or devices to prevent unwanted pregnancy. Birth control has been used since ancient times, but effective and safe methods of birth contr ... if retinoids are used to treat acne. [ Oral antibiotics deemed safe for pregnancy (all category B) include azithromycin, ] cephalosporin
The cephalosporins (sg. ) are a class of β-lactam antibiotics originally derived from the fungus ''Acremonium'', which was previously known as ''Cephalosporium''.
Together with cephamycins, they constitute a subgroup of β-lactam antibiotics ...s, and penicillins. Tetracyclines (category D) are contraindicated during pregnancy as they are known to deposit in developing fetal teeth, resulting in yellow discoloration and thinned tooth enamel. Their use during pregnancy has been associated with the development of acute fatty liver of pregnancy
Acute fatty liver of pregnancy is a rare life-threatening complication of pregnancy that occurs in the third trimester or the immediate period after delivery. It is thought to be caused by a disordered metabolism of fatty acids by mitochondria in ... and is further avoided for this reason.
Limited evidence supports comedo extraction, but it is an option for comedones that do not improve with standard treatment.
Another procedure for immediate relief is the injection of a corticosteroid into an inflamed acne comedo. Electrocautery and electrofulguration are effective alternative treatments for comedones.
Light therapy, also called phototherapy or bright light therapy is intentional daily exposure to direct sunlight or similar-intensity artificial light in order to treat medical disorders, especially seasonal affective disorder (SAD) and circadi ... is a treatment method that involves delivering certain specific wavelengths of light to an area of skin affected by acne. Both regular and laser light
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word "laser" is an acronym for "light amplification by stimulated emission of radiation". The f ... have been used. The evidence for light therapy
Light therapy, also called phototherapy or bright light therapy is intentional daily exposure to direct sunlight or similar-intensity artificial light in order to treat medical disorders, especially seasonal affective disorder (SAD) and circadi ... as a treatment for acne is weak and inconclusive. Various light therapies appear to provide a short-term benefit, but data for long-term outcomes, and outcomes in those with severe acne, are sparse; it may have a role for individuals whose acne has been resistant to topical medications. A 2016 meta-analysis was unable to conclude whether light therapies were more beneficial than placebo or no treatment, nor the duration of benefit.
When regular light is used immediately following the application of a sensitizing substance to the skin such as aminolevulinic acid or methyl aminolevulinate, the treatment is referred to as photodynamic therapy
Photodynamic therapy (PDT) is a form of phototherapy involving light and a photosensitizing chemical substance, used in conjunction with molecular oxygen to elicit cell death (phototoxicity).
PDT is popularly used in treating acne. It is used c ... (PDT). PDT has the most supporting evidence of all light therapy modalities. PDT treats acne by using various forms of light (e.g., blue light or red light) that preferentially target the pilosebaceous unit. Once the light activates the sensitizing substance, this generates free radicals
In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron.
With some exceptions, these unpaired electrons make radicals highly chemically reactive. Many radicals spo ... and reactive oxygen species
In chemistry, reactive oxygen species (ROS) are highly reactive chemicals formed from diatomic oxygen (). Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
The reduction of molecular oxygen () ... in the skin, which purposefully damage the sebaceous glands and kill ''C. acnes'' bacteria. Many different types of nonablative lasers (i.e., lasers that do not vaporize the top layer of the skin but rather induce a physiologic response in the skin from the light) have been used to treat acne, including those that use infrared wavelengths of light. Ablative lasers (such as CO2 and fractional types) have also been used to treat active acne and its scars. When ablative lasers are used, the treatment is often referred to as laser resurfacing because, as mentioned previously, the entire upper layers of the skin are vaporized. Ablative lasers are associated with higher rates of adverse effects compared with non-ablative lasers, with examples being post-inflammatory hyperpigmentation, persistent facial redness, and persistent pain. Physiologically, certain wavelengths of light, used with or without accompanying topical chemicals, are thought to kill bacteria and decrease the size and activity of the glands that produce sebum. Disadvantages of light therapy can include its cost, the need for multiple visits, the time required to complete the procedure(s), and pain associated with some of the treatment modalities. Typical side effects include skin peeling
Desquamation occurs when the outermost layer of a tissue, such as the skin, is shed. The term is . Physiologic desquamation
Keratinocytes are the predominant cells of the epidermis, the outermost layer of the skin. Living keratinocytes reside i ..., temporary reddening of the skin, swelling, and post-inflammatory hyperpigmentation.
Dermabrasion is an effective therapeutic procedure for reducing the appearance of superficial atrophic scars of the boxcar and rolling varieties. Ice-pick scars do not respond well to treatment with dermabrasion due to their depth. The procedure is painful and has many potential side effects such as skin sensitivity to sunlight, redness, and decreased pigmentation of the skin. Dermabrasion has fallen out of favor with the introduction of laser resurfacing. Unlike dermabrasion, there is no evidence that microdermabrasion is an effective treatment for acne.
Dermal or subcutaneous fillers are substances injected into the skin to improve the appearance of acne scars. Fillers are used to increase natural collagen
Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whol ... production in the skin and to increase skin volume and decrease the depth of acne scars. Examples of fillers used for this purpose include hyaluronic acid
Hyaluronic acid (; abbreviated HA; conjugate base hyaluronate), also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. It is unique among glycosaminoglyca ...; poly(methyl methacrylate)
Poly(methyl methacrylate) (PMMA) belongs to a group of materials called engineering plastics. It is a transparent thermoplastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and brands Crylux, Plexiglas, Acryli ... microsphere
Microparticles are particles between 0.1 and 100 μm in size. Commercially available microparticles are available in a wide variety of materials, including ceramics, glass, polymers, and metals. Microparticles encountered in daily life incl ...s with collagen; human and bovine collagen derivatives, and fat harvested from the person's own body (autologous fat transfer).
Microneedling is a procedure in which an instrument with multiple rows of tiny needles is rolled over the skin to elicit a wound healing response and stimulate collagen production to reduce the appearance of atrophic acne scars in people with darker skin color. Notable adverse effects of microneedling include post-inflammatory hyperpigmentation and tram track scarring (described as discrete slightly raised scars in a linear distribution similar to a tram track). The latter is thought to be primarily attributable to improper technique by the practitioner, including the use of excessive pressure or inappropriately large needles.
Subcision is useful for the treatment of superficial atrophic acne scars and involves the use of a small needle to loosen the fibrotic adhesions that result in the depressed appearance of the scar.
Chemical peels can be used to reduce the appearance of acne scars. [ Mild peels include those using glycolic acid, lactic acid, ] salicylic acid
Salicylic acid is an organic compound with the formula HOC6H4CO2H. A colorless, bitter-tasting solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone, and has been listed by the EPA Toxic Subst ..., Jessner's solution, or a lower concentration (20%) of trichloroacetic acid
Trichloroacetic acid (TCA; TCAA; also known as trichloroethanoic acid) is an analogue of acetic acid in which the three hydrogen atoms of the methyl group have all been replaced by chlorine atoms. Salts and esters of trichloroacetic acid are c .... These peels only affect the epidermal layer of the skin and can be useful in the treatment of superficial acne scars as well as skin pigmentation changes from inflammatory acne. [ Higher concentrations of trichloroacetic acid (30–40%) are considered to be medium-strength peels and affect the skin as deep as the papillary dermis.] [ Formulations of trichloroacetic acid concentrated to 50% or more are considered to be deep chemical peels.] [ Medium-strength and deep-strength chemical peels are more effective for deeper atrophic scars but are more likely to cause side effects such as skin pigmentation changes, infection, and small white superficial cysts known as milia.] [
Researchers are investigating complementary therapies as treatment for people with acne.
Low-quality evidence suggests topical application of tea tree oil
Tea tree oil, also known as melaleuca oil, is an essential oil with a fresh camphoraceous odor and a colour that ranges from pale yellow to nearly colourless and clear. It is derived from the leaves of the tea tree, ''Melaleuca alternifolia'', ... or bee venom may reduce the total number of skin lesions in those with acne. Tea tree oil appears to be approximately as effective as benzoyl peroxide or salicylic acid but is associated with allergic contact dermatitis
Allergic contact dermatitis (ACD) is a form of contact dermatitis that is the manifestation of an allergic response caused by contact with a substance; the other type being irritant contact dermatitis (ICD).
Although less common than ICD, ACD is .... [ Proposed mechanisms for tea tree oil's anti-acne effects include antibacterial action against ''C. acnes'' and anti-inflammatory properties.] [ Numerous other plant-derived therapies have demonstrated positive effects against acne (e.g., basil oil; ] oligosaccharide
An oligosaccharide (/ˌɑlɪgoʊˈsækəˌɹaɪd/; from the Greek ὀλίγος ''olígos'', "a few", and σάκχαρ ''sácchar'', "sugar") is a saccharide polymer containing a small number (typically two to ten) of monosaccharides (simple sugar ...s from seaweed
Seaweed, or macroalgae, refers to thousands of species of macroscopic, multicellular, marine algae. The term includes some types of '' Rhodophyta'' (red), ''Phaeophyta'' (brown) and ''Chlorophyta'' (green) macroalgae. Seaweed species such a ...; however, few well-done studies have examined their use for this purpose. There is a lack of high-quality evidence for the use of acupuncture, herbal medicine
Herbal medicine (also herbalism) is the study of pharmacognosy and the use of medicinal plants, which are a basis of traditional medicine. With worldwide research into pharmacology, some herbal medicines have been translated into modern remedi ..., or cupping therapy
Cupping therapy is a form of alternative medicine in which a local suction is created on the skin with the application of heated cups. Its practice mainly occurs in Asia but also in Eastern Europe, the Middle East, and Latin America. Cupping ha ... for acne. [
Many over-the-counter treatments in many forms are available, which are often known as cosmeceuticals. Certain types of makeup may be useful to mask acne.
[ In those with oily skin, a water-based product is often preferred.]
Acne usually improves around the age of 20 but may persist into adulthood.
Permanent physical scarring may occur. [ Rare complications from acne or its treatment include the formation of pyogenic granulomas, osteoma cutis, and acne with facial edema. Early and aggressive treatment of acne is advocated by some in the medical community to reduce the chances of these poor outcomes.]
Mental health impact
There is good evidence to support the idea that acne and associated scarring negatively affect a person's psychological state, worsen mood, lower self-esteem, and are associated with a higher risk of anxiety disorders, depression, and suicidal thoughts.
Misperceptions about acne's causative and aggravating factors are common, and people with acne often blame themselves, and others often blame those with acne for their condition. Such blame can worsen the affected person's sense of self-esteem. Until the 20th century, even among dermatologists, the list of causes was believed to include excessive sexual thoughts and masturbation
Masturbation is the sexual stimulation of one's own genitals for sexual arousal or other sexual pleasure, usually to the point of orgasm. The stimulation may involve hands, fingers, everyday objects, sex toys such as vibrators, or combina .... Dermatology's association with sexually transmitted infections, especially syphilis
Syphilis () is a sexually transmitted infection caused by the bacterium '' Treponema pallidum'' subspecies ''pallidum''. The signs and symptoms of syphilis vary depending in which of the four stages it presents (primary, secondary, latent, a ..., contributed to the stigma.
Psychology is the scientific study of mind and behavior. Psychology includes the study of conscious and unconscious phenomena, including feelings and thoughts. It is an academic discipline of immense scope, crossing the boundaries betwee ... complication of acne vulgaris is acne excoriée, which occurs when a person persistently picks and scratches pimples, irrespective of the severity of their acne. This can lead to significant scarring, changes in the affected person's skin pigmentation, and a cyclic worsening of the affected person's anxiety about their appearance.
Globally, acne affects approximately 650 million people, or about 9.4% of the population, as of 2010.
It affects nearly 90% of people in Western societies during their teenage years, but can occur before adolescence and may persist into adulthood. While acne that first develops between the ages of 21 and 25 is uncommon, it affects 54% of women and 40% of men older than 25 years of age and has a lifetime prevalence of 85%. [ About 20% of those affected have moderate or severe cases.] It is slightly more common in females than males (9.8% versus 9.0%). [ In those over 40 years old, 1% of males and 5% of females still have problems.] [
Rates appear to be lower in rural societies.] While some research has found it affects people of all ethnic groups, acne may not occur in the non-Westernized peoples of Papua New Guinea
Papua New Guinea (abbreviated PNG; , ; tpi, Papua Niugini; ho, Papua Niu Gini), officially the Independent State of Papua New Guinea ( tpi, Independen Stet bilong Papua Niugini; ho, Independen Stet bilong Papua Niu Gini), is a country i ... and Paraguay
Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ....
Acne affects 40–50 million people in the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territo ... (16%) and approximately 3–5 million in Australia (23%). [ Severe acne tends to be more common in people of Caucasian or Amerindian descent than in people of African descent.]
Historical records indicate
Pharaoh (, ; Egyptian: '' pr ꜥꜣ''; cop, , Pǝrro; Biblical Hebrew: ''Parʿō'') is the vernacular term often used by modern authors for the kings of ancient Egypt who ruled as monarchs from the First Dynasty (c. 3150 BC) until the ... had acne, which may be the earliest known reference to the disease. Sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...'s usefulness as a topical remedy for acne dates back to at least the reign of Cleopatra
Cleopatra VII Philopator ( grc-gre, Κλεοπάτρα Φιλοπάτωρ}, "Cleopatra the father-beloved"; 69 BC10 August 30 BC) was Queen of the Ptolemaic Kingdom of Egypt from 51 to 30 BC, and its last active ruler.She was also ... (69–30 BCE). The sixth-century Greek physician Aëtius of Amida reportedly coined the term "" (,) or "", which seems to be a reference to facial skin lesions that occur during "the ' acme' of life" ( puberty
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a boy ...).
In the 16th century, the French physician and botanist François Boissier de Sauvages de Lacroix provided one of the earlier descriptions of acne. He used the term "psydracia achne" to describe small, red, and hard tubercles that altered a person's facial appearance during adolescence and were neither itchy nor painful. [
The recognition and characterization of acne progressed in 1776 when Josef Plenck (an ] Austria
Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populou ...n physician) published a book that proposed the novel concept of classifying skin diseases by their elementary (initial) lesions. [ In 1808 the English ] dermatologist
Dermatology is the branch of medicine dealing with the skin.''Random House Webster's Unabridged Dictionary.'' Random House, Inc. 2001. Page 537. . It is a speciality with both medical and surgical aspects. A dermatologist is a specialist medi ... Robert Willan refined Plenck's work by providing the first detailed descriptions of several skin disorders using morphologic terminology that remains in use today. [ Thomas Bateman continued and expanded on Robert Willan's work as his student and provided the first descriptions and illustrations of acne accepted as accurate by modern dermatologists.] [ Erasmus Wilson, in 1842, was the first to make the distinction between acne vulgaris and rosacea. The first professional medical ] monograph
A monograph is a specialist work of writing (in contrast to reference works) or exhibition on a single subject or an aspect of a subject, often by a single author or artist, and usually on a scholarly subject.
In library cataloging, ''monogra ... dedicated entirely to acne was written by Lucius Duncan Bulkley and published in New York in 1885.
Scientists initially hypothesized that acne represented a disease of the skin's hair follicle, and occurred due to blockage of the pore by sebum. During the 1880s, they observed bacteria by microscopy in skin samples from people with acne. Investigators believed the bacteria caused comedones, sebum production, and ultimately acne. [ During the mid-twentieth century, dermatologists realized that no single hypothesized factor (sebum, bacteria, or excess keratin) fully accounted for the disease in its entirety.] [ This led to the current understanding that acne could be explained by a sequence of related events, beginning with blockage of the skin follicle by excessive dead skin cells, followed by bacterial invasion of the hair follicle pore, changes in sebum production, and inflammation.] [
The approach to acne treatment underwent significant changes during the twentieth century. Retinoids became a medical treatment for acne in 1943.] Benzoyl peroxide was first proposed as a treatment in 1958 and remains a staple of acne treatment. The introduction of oral tetracycline antibiotics (such as minocycline) modified acne treatment in the 1950s. These reinforced the idea amongst dermatologists that bacterial growth on the skin plays an important role in causing acne. [ Subsequently, in the 1970s, tretinoin (original trade name Retin A) was found to be an effective treatment.] The development of oral isotretinoin
Isotretinoin, also known as 13-''cis''-retinoic acid and sold under the brand name Accutane among others, is a medication primarily used to treat severe acne. It is also used to prevent certain skin cancers (squamous-cell carcinoma), and in th ... (sold as Accutane and Roaccutane) followed in 1980. After its introduction in the United States, scientists identified isotretinoin as a medication highly likely to cause birth defects if taken during pregnancy. In the United States, more than 2,000 women became pregnant while taking isotretinoin between 1982 and 2003, with most pregnancies ending in abortion
Abortion is the termination of a pregnancy by removal or expulsion of an embryo or fetus. An abortion that occurs without intervention is known as a miscarriage or "spontaneous abortion"; these occur in approximately 30% to 40% of preg ... or miscarriage
Miscarriage, also known in medical terms as a spontaneous abortion and pregnancy loss, is the death of an embryo or fetus before it is able to survive independently. Miscarriage before 6 weeks of gestation is defined by ESHRE as biochemical .... Approximately 160 babies were born with birth defects due to maternal use of isotretinoin during pregnancy.
Treatment of acne with topical crushed dry ice, known as cryoslush, was first described in 1907 but is no longer performed commonly. Before 1960, the use of X-rays was also a common treatment.
Society and culture
The costs and social impact of acne are substantial. In the United States, acne vulgaris is responsible for more than 5 million
Doctor or The Doctor may refer to:
* Doctor (title), the holder of an accredited academic degree
* A medical practitioner, including:
** Veterinary physician
*Other roles ... visits and costs over billion each year in direct costs. Similarly, acne vulgaris is responsible for 3.5 million doctor visits each year in the United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and No .... [ Sales for the top ten leading acne treatment brands in the US in 2015 amounted to $352million.
Acne vulgaris and its resultant scars are associated with significant social and academic difficulties that can last into adulthood.] During the Great Depression
The Great Depression (19291939) was an economic shock that impacted most countries across the world. It was a period of economic depression that became evident after a major fall in stock prices in the United States. The Financial contagion, ..., dermatologists discovered that young men with acne had difficulty obtaining jobs. Until the 1930s, many people viewed acne as a trivial problem among middle-class girls because, unlike smallpox
Smallpox was an infectious disease caused by variola virus (often called smallpox virus) which belongs to the genus Orthopoxvirus. The last naturally occurring case was diagnosed in October 1977, and the World Health Organization (WHO) c ... and tuberculosis
Tuberculosis (TB) is an infectious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, in w ..., no one died from it, and a feminine problem, because boys were much less likely to seek medical assistance for it. During World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ..., some soldiers in tropical climates developed such severe and widespread tropical acne on their bodies that they were declared medically unfit for duty.
Efforts to better understand the mechanisms of sebum production are underway. This research aims to develop medications that target and interfere with the hormones that are known to increase sebum production (e.g.,
Insulin-like growth factor 1 (IGF-1), also called somatomedin C, is a hormone similar in molecular structure to insulin which plays an important role in childhood growth, and has anabolic effects in adults.
IGF-1 is a protein that in humans ... and alpha-melanocyte-stimulating hormone). Other sebum-lowering medications such as topical antiandrogens, peroxisome proliferator-activated receptor
In the field of molecular biology, the peroxisome proliferator-activated receptors (PPARs) are a group of nuclear receptor proteins that function as transcription factors regulating the expression of genes. PPARs play essential roles in the ... modulators, and inhibitors of the stearoyl-CoA desaturase-1 enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. ... are also a focus of research efforts. Particles that release nitric oxide
Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its ... into the skin to decrease skin inflammation caused by ''C. acnes'' and the immune system
The immune system is a network of biological processes that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splint ... have shown promise for improving acne in early clinical trials. Another avenue of early-stage research has focused on how to best use laser and light therapy to selectively destroy sebum-producing glands in the skin's hair follicles to reduce sebum production and improve acne appearance.
The use of antimicrobial peptides
Antimicrobial peptides (AMPs), also called host defence peptides (HDPs) are part of the innate immune response found among all classes of life. Fundamental differences exist between prokaryotic and eukaryotic cells that may represent targets for ... against ''C. acnes'' is under investigation as a treatment for acne to overcoming antibiotic resistance. In 2007, scientists reported the first genome
In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ... sequencing
In genetics and biochemistry, sequencing means to determine the primary structure (sometimes incorrectly called the primary sequence) of an unbranched biopolymer. Sequencing results in a symbolic linear depiction known as a sequence which suc ... of a ''C. acnes'' bacteriophage
A bacteriophage (), also known informally as a ''phage'' (), is a duplodnaviria virus that infects and replicates within bacteria and archaea. The term was derived from "bacteria" and the Greek φαγεῖν ('), meaning "to devour". Bacter ... (PA6). The authors proposed applying this research toward the development of bacteriophage therapy as an acne treatment to overcome the problems associated with long-term antibiotic use, such as bacterial resistance. Oral and topical probiotics are under evaluation as treatments for acne. Probiotics may have therapeutic effects for those affected by acne due to their ability to decrease skin inflammation and improve skin moisture by increasing the skin's ceramide
Ceramides are a family of waxy lipid molecules. A ceramide is composed of N-acetylsphingosine and a fatty acid. Ceramides are found in high concentrations within the cell membrane of eukaryotic cells, since they are component lipids that make ... content. [ As of 2014, knowledge of the effects of probiotics on acne in humans was limited.] [
Decreased levels of retinoic acid in the skin may contribute to comedo formation. Researchers are investigating methods to increase the skin's production of retinoic acid to address this deficiency.] A vaccine
A vaccine is a biological preparation that provides active acquired immunity to a particular infectious or malignant disease. The safety and effectiveness of vaccines has been widely studied and verified. against inflammatory acne has shown promising results in mice and humans. [ Some have voiced concerns about creating a vaccine designed to neutralize a stable community of normal skin bacteria that is known to protect the skin from colonization by more harmful microorganisms.
Acne can occur on cats, dogs, and horses.
Expert, impartial advice on acne by the BAD.
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