A scar (or scar tissue) is an area of
fibrous tissue
Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...
that replaces normal
skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...
after an
injury
An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, o ...
. Scars result from the biological process of
wound repair
Wound healing refers to a living organism's replacement of destroyed or damaged tissue by newly produced tissue.
In undamaged skin, the epidermis (surface, epithelial layer) and dermis (deeper, connective layer) form a protective barrier agains ...
in the skin, as well as in other
organs, and
tissues of the body. Thus, scarring is a natural part of the
healing
With physical trauma or disease suffered by an organism, healing involves the repairing of damaged tissue(s), organs and the biological system as a whole and resumption of (normal) functioning. Medicine includes the process by which the cells i ...
process. With the exception of very minor
lesion
A lesion is any damage or abnormal change in the tissue of an organism, usually caused by disease or trauma. ''Lesion'' is derived from the Latin "injury". Lesions may occur in plants as well as animals.
Types
There is no designated classifi ...
s, every wound (e.g., after
accident
An accident is an unintended, normally unwanted event that was not directly caused by humans. The term ''accident'' implies that nobody should be blamed, but the event may have been caused by unrecognized or unaddressed risks. Most researcher ...
,
disease
A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
, or
surgery
Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...
) results in some degree of scarring. An exception to this are animals with complete
regeneration
Regeneration may refer to:
Science and technology
* Regeneration (biology), the ability to recreate lost or damaged cells, tissues, organs and limbs
* Regeneration (ecology), the ability of ecosystems to regenerate biomass, using photosynthesis
...
, which regrow tissue without scar formation.
Scar tissue is composed of the same protein (
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 whole ...
) as the tissue that it replaces, but the fiber composition of the protein is different; instead of a random basketweave formation of the collagen fibers found in normal tissue, in fibrosis the collagen cross-links and forms a pronounced alignment in a single direction.
This collagen scar tissue alignment is usually of inferior functional quality to the normal collagen randomised alignment. For example, scars in the skin are less resistant to
ultraviolet radiation
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
, and
sweat gland
Sweat glands, also known as sudoriferous or sudoriparous glands, , are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial sur ...
s and
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 between h ...
s do not grow back within scar tissues.
[ A ]myocardial infarction
A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which may ...
, commonly known as a heart attack, causes scar formation in the heart
The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...
muscle, which leads to loss of muscular power and possibly heart failure
Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...
. However, there are some tissues (e.g. bone
A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
) that can heal without any structural or functional deterioration.
Types
All scarring is composed of the same collagen as the tissue it has replaced, but the composition of the scar tissue, compared to the normal tissue, is different.[ Scar tissue also lacks elasticity] unlike normal tissue which distributes fiber elasticity. Scars differ in the amounts of collagen overexpressed. Labels have been applied to the differences in overexpression. Two of the most common types are hypertrophic and keloid
Keloid, also known as keloid disorder and keloidal scar,
is the formation of a type of scar which, depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen. It is a result of an overgrowth of granulation t ...
scarring,[ both of which experience excessive stiff collagen bundled growth overextending the tissue, blocking off regeneration of tissues. Another form is atrophic scarring (sunken scarring), which also has an overexpression of collagen blocking regeneration. This scar type is sunken, because the collagen bundles do not overextend the tissue. Stretch marks (striae) are regarded as scars by some.
High ]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 amino ...
levels and either African or Asian ancestry may make adverse scarring more noticeable.
Hypertrophic
Hypertrophic scars
A hypertrophic scar is a cutaneous condition characterized by deposits of excessive amounts of collagen which gives rise to a raised scar, but not to the degree observed with keloids. Like keloids, they form most often at the sites of pimples, body ...
occur when the body overproduces 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 whole ...
, which causes the scar to be raised above the surrounding skin. Hypertrophic
Hypertrophy is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It is distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number.Updated by Linda J ...
scars take the form of a red raised lump on the skin for lighter pigmented skin and the form of dark brown for darker pigmented skin. They usually occur within 4 to 8 weeks following wound infection or wound closure with excess tension and/or other traumatic skin injuries.
Keloid
Keloid scars are a more serious form of excessive scarring, because they can grow indefinitely into large, tumorous (although benign) neoplasm
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 ...
s.[
Hypertrophic scars are often distinguished from keloid scars by their lack of growth outside the original wound area, but this commonly taught distinction can lead to confusion.]
Keloid scars can occur on anyone, but they are most common in dark-skinned people. They can be caused by surgery, accident, acne
Acne, also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, black ...
or, sometimes, body piercings
Body piercing, which is a form of body modification, is the practice of puncturing or cutting a part of the human body, creating an opening in which jewelry may be worn, or where an Implant (medicine), implant could be inserted. The word ''pier ...
. In some people, keloid scars form spontaneously. Although they can be a cosmetic problem, keloid scars are only inert masses of collagen and therefore completely harmless and not cancerous. However, they can be itchy or painful in some individuals. They tend to be most common on the shoulder
The human shoulder is made up of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone) as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder mak ...
s and chest
The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the crea ...
. Hypertrophic scars and keloids tend to be more common in wounds closed by secondary intention.[ Surgical removal of keloid is risky and may exacerbate the condition and worsening of the keloid.
]
Atrophic
An atrophic scar takes the form of a sunken recess in the skin, which has a pitted appearance. These are caused when underlying structures supporting the skin, such as fat
In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food.
The term often refers spec ...
or muscle
Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...
, are lost. This type of scarring is often associated with acne, chickenpox
Chickenpox, also known as varicella, is a highly contagious disease caused by the initial infection with varicella zoster virus (VZV). The disease results in a characteristic skin rash that forms small, itchy blisters, which eventually scab ...
, other diseases (especially ''Staphylococcus
''Staphylococcus'' is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillales. Under the microscope, they appear spherical (cocci), and form in grape-like clusters. ''Staphylococcus'' species are facultative ...
'' infection), surgery, certain insect and spider bites, or accidents. It can also be caused by a genetic 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 ...
disorder, such as Ehlers–Danlos syndrome.
Stretch marks
Stretch marks (technically called ''striae'') are also a form of scarring. These are caused when the skin is stretched rapidly (for instance during pregnancy
Pregnancy is the time during which one or more offspring develops ( gestates) inside a woman's uterus (womb). A multiple pregnancy involves more than one offspring, such as with twins.
Pregnancy usually occurs by sexual intercourse, but ca ...
, significant weight gain
Weight gain is an increase in body weight. This can involve an increase in muscle mass, fat deposits, excess fluids such as water or other factors. Weight gain can be a symptom of a serious medical condition.
Description
Weight gain occurs wh ...
, or adolescent growth spurt
Human height or stature is the distance from the bottom of the feet to the top of the head in a human body, standing erect. It is measured using a stadiometer, in centimetres when using the metric system or SI system, or feet and inches when u ...
s), or when skin is put under tension during the healing process (usually near joints
A joint or articulation (or articular surface) is the connection made between bones, ossicles, or other hard structures in the body which link an animal's skeletal system into a functional whole.Saladin, Ken. Anatomy & Physiology. 7th ed. McGraw- ...
). This type of scar usually improves in appearance after a few years.
Elevated corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involv ...
levels are implicated in striae development.
Umbilical
Humans and other placental mammal
Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguishe ...
s have an umbilical scar (commonly referred to as a navel
The navel (clinically known as the umbilicus, commonly known as the belly button or tummy button) is a protruding, flat, or hollowed area on the abdomen at the attachment site of the umbilical cord. All placental mammals have a navel, although ...
) which starts to heal when the umbilical cord
In placental mammals, the umbilical cord (also called the navel string, birth cord or ''funiculus umbilicalis'') is a conduit between the developing embryo or fetus and the placenta. During prenatal development, the umbilical cord is physiologic ...
is cut after birth. Egg-laying animals have an umbilical scar which, depending on the species, may remain visible for life or disappear within a few days after birth.
Pathophysiology
A scar is the product of the body's repair mechanism after tissue injury. If a wound heals quickly within two weeks with new formation of skin, minimal collagen will be deposited and no scar will form. When the extracellular matrix senses elevated mechanical stress loading, tissue will scar,[ and scars can be limited by stress shielding wounds.] Small full thickness wounds under 2mm reepithelize fast and heal scar free. Deep second-degree burns heal with scarring and hair loss
Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarri ...
. Sweat glands do not form in scar tissue, which impairs the regulation of body temperature. Elastic fibers are generally not detected in scar tissue younger than 3 months old. In scars, rete pegs
Rete pegs (also known as rete processes or rete ridges) are the epithelial extensions that project into the underlying connective tissue in both skin and mucous membranes.
In the epithelium of the mouth, the attached gingiva exhibit rete pegs, wh ...
are lost;[ through a lack of rete pegs, scars tend to shear easier than normal tissue.]
The endometrium
The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The functional laye ...
, the inner lining of the uterus, is the only adult tissue to undergo rapid cyclic shedding and regeneration without scarring, shedding and restoring roughly inside a 7-day window on a monthly basis. All other adult tissues, upon rapid shedding or injury, can scar.
Prolonged inflammation
Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
, as well as the fibroblast
A fibroblast is a type of cell (biology), biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (Stroma (tissue), stroma) for animal Tissue (biology), tissues, and plays a critical role in wound ...
proliferation, can occur. Redness that often follows an injury to the skin is not a scar and is generally not permanent (see wound healing
Wound healing refers to a living organism's replacement of destroyed or damaged tissue by newly produced tissue.
In undamaged skin, the epidermis (surface, epithelial layer) and dermis (deeper, connective layer) form a protective barrier again ...
). The time it takes for this redness to dissipate may, however, range from a few days to, in some serious and rare cases, a few years.
Scars form differently based on the location of the injury on the body and the age of the person who was injured.
The worse the initial damage is, the worse the scar will generally be.
Skin scars occur when 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 i ...
(the deep, thick layer of skin) is damaged. Most skin scars are flat and leave a trace of the original injury
An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, o ...
that caused them.
Wounds allowed to heal secondarily tend to scar worse than wounds from primary closure.
Collagen synthesis
An injury does not become a scar until the wound has completely healed; this can take many months, or years in the worst pathological cases, such as keloids. To begin to patch the damage, a clot
A thrombus (plural thrombi), colloquially called a blood clot, is the final product of the blood coagulation step in hemostasis. There are two components to a thrombus: aggregated platelets and red blood cells that form a plug, and a mesh of c ...
is created; this clot is the beginning process that results in a provisional matrix. In the process, the first layer is a provisional matrix and is not a scar. Over time, the wounded body tissue overexpresses 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 whole ...
inside the provisional matrix to create a collagen matrix. This collagen overexpression continues and crosslinks the fiber arrangement inside the collagen matrix, making the collagen dense. This densely packed collagen, morphing into an inelastic whitish collagen scar wall, blocks off cell communication and regeneration; as a result, the new tissue generated will have a different texture and quality than the surrounding unwounded tissue. This prolonged collagen-producing process results in a fortuna scar.
Fibroblasts
The scarring is created by fibroblast
A fibroblast is a type of cell (biology), biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (Stroma (tissue), stroma) for animal Tissue (biology), tissues, and plays a critical role in wound ...
proliferation, a process that begins with a reaction to the clot. To mend the damage, fibroblasts slowly form the 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 whole ...
scar. The fibroblast proliferation is circular[ and cyclically, the fibroblast proliferation lays down thick, whitish collagen] inside the provisional and collagen matrix, resulting in the abundant production of packed collagen on the fibers[ giving scars their uneven texture. Over time, the fibroblasts continue to crawl around the matrix, adjusting more fibers and, in the process, the scarring settles and becomes stiff.][ This fibroblast proliferation also contracts the tissue.][ In unwounded tissue, these fibers are not overexpressed with thick collagen and do not contract.
EPF and ENF fibroblasts have been genetically traced with the Engrailed-1 genetic marker.][ EPFs are the primary contributors to all fibrotic outcomes after wounding.][ ENFs do not contribute to fibrotic outcomes.]
Myofibroblast
Mammalian wounds that involve the dermis of the skin heal by repair, not regeneration (except in 1st trimester inter-uterine wounds and in the regeneration of deer antlers). Full-thickness wounds heal by a combination of wound contracture and edge re-epitheliasation. Partial thickness wounds heal by edge re-epithelialisation and epidermal migration from adnexal structures (hair follicles, sweat glands and sebaceous glands). The site of keratinocyte
Keratinocytes are the primary type of Cell (biology), cell found in the epidermis (skin), epidermis, the outermost layer of the skin. In humans, they constitute 90% of epidermal skin cells.
Basal cells in the stratum basale, basal layer (''str ...
stem cells remains unknown but stem cells are likely to reside in the basal layer
The ''stratum basale'' (basal layer, sometimes referred to as ''stratum germinativum'') is the deepest layer of the five layers of the epidermis, the external covering of skin in mammals.
The ''stratum basale'' is a single layer of columnar or ...
of 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 rele ...
and below the bulge area of hair follicles.
The fibroblast involved in scarring and contraction is the myofibroblast
A myofibroblast is a cell phenotype that was first described as being in a state between a fibroblast and a smooth muscle cell.
Structure
Myofibroblasts are contractile web-like fusiform cells that are identifiable by their expression of α-sm ...
, which is a specialized contractile fibroblast. These cells express α-smooth muscle actin (α-SMA).
The myofibroblasts are absent in the first trimester in the embryonic stage where damage heals scar-free;[ in small incisional or excision wounds less than 2 mm that also heal without scarring;][ and in adult unwounded tissues where the fibroblast in itself is arrested; however, the myofibroblast is found in massive numbers in adult wound healing which heals with a scar.][
The myofibroblasts make up a high proportion of the fibroblasts proliferating in the postembryonic wound at the onset of healing. In the rat model, for instance, myofibroblasts can constitute up to 70% of the fibroblasts,] and is responsible for fibrosis on tissue. Generally, the myofibroblasts disappear from the wound within 30 days,[ but can remain in pathological cases in ]hypertrophy
Hypertrophy is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It is distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number.Updated by Linda J ...
, such as keloids. Myofibroblasts have plasticity and in mice can be transformed into fat cells, instead of scar tissue, via the regeneration of hair follicles.
Mechanical stress
Wounds under 2mm generally do not scar[ but larger wounds generally do scar.][ In 2011 it was found that mechanical stress can stimulate scarring][ and that stress shielding can reduce scarring in wounds.][ In 2021 it was found that using chemicals to manipulate fibroblasts to not sense mechanical stress brought scar-free healing.][ The scar-free healing also occurred when mechanical stress was placed onto a wound.]
Treatment
Early and effective treatment of acne scarring can prevent severe acne and the scarring that often follows. In 2004, no prescription drugs for the treatment or prevention of scars were available.
Chemical peels
Chemical peels are chemicals which destroy the epidermis in a controlled manner, leading to exfoliation and the alleviation of certain skin conditions, including superficial acne scars. Various chemicals can be used depending upon the depth of the peel, and caution should be used, particularly for dark-skinned individuals and those individuals susceptible to keloid
Keloid, also known as keloid disorder and keloidal scar,
is the formation of a type of scar which, depending on its maturity, is composed mainly of either type III (early) or type I (late) collagen. It is a result of an overgrowth of granulation t ...
formation or with active infections.
Filler injections
Filler injections of 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 whole ...
can be used to raise atrophic
Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply t ...
scars to the level of surrounding skin. Risks vary based upon the filler used, and can include further disfigurement and allergic reaction
Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...
.
Laser treatment
Nonablative lasers, such as the 585 nm pulsed dye laser
A dye laser is a laser that uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths, often spanning 50 to 100 ...
, 1064 nm and 1320 nm Nd:YAG, or the 1540 nm Er:Glass are used as laser therapy for hypertrophic scars and keloids. There is tentative evidence for burn scars that they improve the appearance.
Ablative lasers such as the carbon dioxide laser
The carbon-dioxide laser (CO2 laser) was one of the earliest gas lasers to be developed. It was invented by Kumar Patel of Bell Labs in 1964 and is still one of the most useful types of laser. Carbon-dioxide lasers are the highest-power continuou ...
(CO) or Er:YAG offer the best results for atrophic and acne scars. Like dermabrasion
Dermabrasion is a type of surgical skin planing, generally with the goal of removing acne, scarring and other skin or tissue irregularities, typically performed in a professional medical setting by a dermatologist or plastic surgeon trained speci ...
, ablative lasers work by removing the epidermis. Healing times for ablative therapy are much longer and the risk profile is greater compared to nonablative therapy; however, nonablative therapy offers only minor improvements in cosmetic appearance of atrophic and acne scars.
Combination laser therapy and microneedling
Collagen induction therapy (CIT), also known as microneedling, dermarolling, or skin needling, is a Medical aesthetics, cosmetic procedure that involves repeatedly puncturing the Human skin, skin with tiny, sterile needles (microneedling the skin) ...
may offer superior results to single modality treatment. The biggest recent advance in scar management is the use of fractionated CO laser and immediate application of topical steroid Triamcinolone
Triamcinolone is a glucocorticoid used to treat certain skin diseases, allergies, and rheumatic disorders among others. It is also used to prevent worsening of asthma and COPD. It can be taken in various ways including by mouth, injection into ...
.
Radiotherapy
Low-dose, superficial radiotherapy
Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radia ...
is sometimes used to prevent recurrence of severe keloid and hypertrophic scarring. It is thought to be effective despite a lack of clinical trials, but only used in extreme cases due to the perceived risk of long-term side effects.
Dressings and topical silicone
Silicone scar treatments are commonly used in preventing scar formation and improving existing scar appearance. A meta-study
A meta-analysis is a statistical analysis that combines the results of multiple scientific studies. Meta-analyses can be performed when there are multiple scientific studies addressing the same question, with each individual study reporting me ...
by the Cochrane collaboration
Cochrane (previously known as the Cochrane Collaboration) is a British international charitable organisation formed to organise medical research findings to facilitate evidence-based choices about health interventions involving health profess ...
found weak evidence that silicone gel sheeting helps prevent scarring.[ However, the studies examining it were of poor quality and susceptible to bias.]
Pressure dressing
A dressing is a sterile pad or compress applied to a wound to promote healing and protect the wound from further harm. A dressing is designed to be in direct contact with the wound, as distinguished from a bandage, which is most often used to hol ...
s are commonly used in managing burn and hypertrophic scars, although supporting evidence is lacking. Care providers commonly report improvements, however, and pressure therapy has been effective in treating ear keloids.[ The general acceptance of the treatment as effective may prevent it from being further studied in clinical trials.][
]
Verapamil-containing silicone gel
Verapamil, a type of calcium channel blocker, is considered a candidate drug for the treatment of hypertrophic scars. A study conducted by the catholic university of Korea concluded that verapamil‐releasing silicone gel is effective and is a superior alternative to the conventional silicone gel where decreased median SEI, fibroblast count, and collagen density in all verapamil‐added treatment groups were observed Gross morphologic features suggested that the combination of verapamil and silicone improves the overall quality of hypertrophic scars by reducing scar height and redness. This was verified with quantifiable histomorphometric parameters. but Oral verapamil is not a good choice because of its effect of lowering blood pressure. Intralesional injection of verapamil is also suboptimal because of the required frequency for injections. Topical silicone gel combined with verapamil does not lead to systemic hypotension, is convenient to apply, and shows enhanced results.
Steroids
A long-term course of corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involv ...
injections into the scar may help flatten and soften the appearance of keloid or hypertrophic scars.
Topical steroids are ineffective.[Jenkins M, Alexander JW, MacMillan BG, Waymack JP, Kopcha R. Failure of topical steroids and vitamin E to reduce postoperative scar formation following reconstructive surgery. J Burn Care Rehabil. 1986 Jul–Aug;7(4):309–312.] However, clobetasol propionate
Clobetasol propionate is a corticosteroid used to treat skin conditions such as eczema, contact dermatitis, seborrheic dermatitis, and psoriasis. It is applied to the skin as a cream, ointment, or shampoo. Use should be short term and only if ot ...
can be used as an alternative treatment for keloid scars.
Topical steroid applied immediately after fractionated CO2 laser treatment is however very effective (and more efficacious than laser treatment alone) and has shown benefit in numerous clinical studies.
Surgery
Scar revision is a process of cutting the scar tissue out. After the excision, the new wound is usually closed up to heal by primary intention
Wound healing refers to a living organism's replacement of destroyed or damaged tissue by newly produced tissue.
In undamaged skin, the epidermis (surface, epithelial layer) and dermis (deeper, connective tissue, connective layer) form a protect ...
, instead of secondary intention
Wound healing refers to a living organism's replacement of destroyed or damaged tissue by newly produced tissue.
In undamaged skin, the epidermis (surface, epithelial layer) and dermis (deeper, connective layer) form a protective barrier agains ...
. Deeper cuts need a multilayered closure to heal optimally, otherwise depressed or dented scars can result.
Surgical excision of hypertrophic or keloid scars is often associated to other methods, such as pressotherapy or silicone gel sheeting. Lone excision of keloid scars, however, shows a recurrence rate close to 45%. A clinical study is currently ongoing to assess the benefits of a treatment combining surgery and laser-assisted healing in hypertrophic or keloid scars.
''Subcision'' is a process used to treat deep rolling scars left behind by acne
Acne, also known as ''acne vulgaris'', is a long-term Cutaneous condition, skin condition that occurs when Keratinocyte, dead skin cells and Sebum, oil from the skin clog hair follicles. Typical features of the condition include comedo, black ...
or other skin diseases. It is also used to lessen the appearance of severe glabella
The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior to ...
lines, though its effectiveness in this application is debatable. Essentially the process involves separating the skin tissue in the affected area from the deeper scar tissue. This allows the blood to pool under the affected area, eventually causing the deep rolling scar to level off with the rest of the skin area. Once the skin has leveled, treatments such as laser resurfacing
Photorejuvenation is a skin treatment that uses lasers, intense pulsed light, or photodynamic therapy to treat skin conditions and remove effects of photoaging such as wrinkles, spots, and textures. The process induces controlled wounds to the sk ...
, microdermabrasion
Dermabrasion is a type of surgical skin planing, generally with the goal of removing acne, scarring and other skin or tissue irregularities, typically performed in a professional medical setting by a dermatologist or plastic surgeon trained speci ...
or chemical peel
A chemical peel is a technique used to improve and smooth the texture of the skin. Facial skin is mostly treated, and scarring can be improved. Chemical peels are intended to remove the outermost layers of the skin. To accomplish this task, the ch ...
s can be used to smooth out the scarred tissue.
Vitamins
Research shows the use of vitamin E
Vitamin E is a group of eight fat soluble compounds that include four tocopherols and four tocotrienols. Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitami ...
and onion extract (sold as Mederma Mederma is a topical product used to improve scar appearance. It is a gel based on an onion extract and produced by Merz Pharmaceuticals of Frankfurt, Germany, although it is not sold in Germany. Mederma's marketing claims it can make scars "softer, ...
) as treatments for scars is ineffective.[ Vitamin E causes contact ]dermatitis
Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can v ...
in up to 33% of users and in some cases it may worsen scar appearance and could cause minor skin irritations, but Vitamin C
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...
and some of its esters
In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides are ...
fade the dark pigment associated with some scars.[Farris PK. Topical vitamin C: a useful agent for treating photoaging and other dermatologic conditions. Although many people claim that vitamin therapy does in fact help. Dermatol Surg 2005;31:814-818.]
Other
* Cosmetics; Medical makeup can temporarily conceal scars. This is most commonly used for facial
A facial is a family of skin care treatments for the face, including steam, exfoliation (physical and chemical), extraction, creams, lotions, facial masks, peels, and massage. They are normally performed in beauty salons, but are also a com ...
scars.
* Dermabrasion
Dermabrasion is a type of surgical skin planing, generally with the goal of removing acne, scarring and other skin or tissue irregularities, typically performed in a professional medical setting by a dermatologist or plastic surgeon trained speci ...
involves the removal of the surface of the skin with special equipment, and usually involves a local anaesthetic
A local anesthetic (LA) is a medication that causes absence of pain sensation. In the context of surgery, a local anesthetic creates an absence of pain in a specific location of the body without a loss of consciousness, as opposed to a general an ...
.
* Massage
Massage is the manipulation of the body's soft tissues. Massage techniques are commonly applied with hands, fingers, elbows, knees, forearms, feet or a device. The purpose of massage is generally for the treatment of body stress or pain. In Eu ...
has weak evidence of efficacy in scar management. Any beneficial effect appears to be greater in wounds created by surgical incision
In surgery, a surgical incision is a cut made through the skin and soft tissue to facilitate an Surgery, operation or medical procedure, procedure. Often, multiple incisions are possible for an operation. In general, a surgical incision is made as ...
than traumatic wounds or burn
A burn is an injury to skin, or other tissues, caused by heat, cold, electricity, chemicals, friction, or ultraviolet radiation (like sunburn). Most burns are due to heat from hot liquids (called scalding), solids, or fire. Burns occur mainl ...
wounds.
* Microneedling
Collagen induction therapy (CIT), also known as microneedling, dermarolling, or skin needling, is a Medical aesthetics, cosmetic procedure that involves repeatedly puncturing the Human skin, skin with tiny, sterile needles (microneedling the skin) ...
Society and culture
Intentional scarring
The permanence of scarring has led to its intentional use as a form of body art
Body art is art made on, with, or consisting of, the human body. Body art covers a wide spectrum including tattoos, body piercings, scarification, and body painting. Body art may include performance art, body art is likewise utilized for investiga ...
within some cultures and subcultures. These forms of ritual and non-ritual scarring practices can be found in many groups and cultures around the world.
Etymology
First attested in English in the late 14th century, the word ''scar'' derives from a conflation of Old French
Old French (, , ; Modern French: ) was the language spoken in most of the northern half of France from approximately the 8th to the 14th centuries. Rather than a unified language, Old French was a linkage of Romance dialects, mutually intelligib ...
''escharre'', from Late Latin
Late Latin ( la, Latinitas serior) is the scholarly name for the form of Literary Latin of late antiquity.Roberts (1996), p. 537. English dictionary definitions of Late Latin date this period from the , and continuing into the 7th century in t ...
''eschara'', which is the latinisation of the Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, an ethnic group.
*Greek language, a branch of the Indo-European language family.
**Proto-Greek language, the assumed last common ancestor ...
ἐσχάρα (''eskhara''), meaning "hearth, fireplace", but in medicine "scab, eschar
An eschar (; Greek: ''ἐσχάρᾱ'', ''eskhara''; Latin: ''eschara'') is a slough or piece of dead tissue that is cast off from the surface of the skin, particularly after a burn injury, but also seen in gangrene, ulcer, fungal infections, ...
on a wound caused by burning or otherwise",[Online Etymology Dictionary](_blank)
/ref> and Middle English
Middle English (abbreviated to ME) is a form of the English language that was spoken after the Norman conquest of 1066, until the late 15th century. The English language underwent distinct variations and developments following the Old English p ...
''skar'' ("cut, crack, incision"), which is from Old Norse
Old Norse, Old Nordic, or Old Scandinavian, is a stage of development of North Germanic languages, North Germanic dialects before their final divergence into separate Nordic languages. Old Norse was spoken by inhabitants of Scandinavia and t ...
''skarð'' ("notch, gap"). The conflation helped to form the English meaning. Compare Scarborough Scarborough or Scarboro may refer to:
People
* Scarborough (surname)
* Earl of Scarbrough
Places Australia
* Scarborough, Western Australia, suburb of Perth
* Scarborough, New South Wales, suburb of Wollongong
* Scarborough, Queensland, su ...
for evolution of ''skarð'' to ''scar''.
Research
Treatment
Research, before 2009, focused on scar improvements with research in to molecular mechanisms. Molecular mechanisms such as: juvista, ribosomal s6 kinase
In molecular biology, ribosomal s6 kinase (rsk) is a family of protein kinases involved in signal transduction. There are two subfamilies of rsk, p90rsk, also known as MAPK-activated protein kinase-1 (MAPKAP-K1), and p70rsk, also known as S6-H1 ...
(RSK), and osteopontin
Osteopontin (OPN), also known as bone /sialoprotein I (BSP-1 or BNSP), early T-lymphocyte activation (ETA-1), secreted phosphoprotein 1 (SPP1), 2ar and Rickettsia resistance (Ric), is a protein that in humans is encoded by the ''SPP1'' gene (secr ...
were investigated.
In 2011, the scientific literature highlighted stress shielding a fresh wound through the wound healing process, brings significant scar improvement and smaller scars.
Prevention
By 2016, skin had been regenerated ''in vivo
Studies that are ''in vivo'' (Latin for "within the living"; often not italicized in English) are those in which the effects of various biological entities are tested on whole, living organisms or cells, usually animals, including humans, and ...
'', and ''in vitro
''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology an ...
'' and scar free healing had been operationalized and induced by four main techniques: regeneration by instrument; regeneration by materials; regeneration by drugs; and regeneration by ''in vitro'' 3-D printing. In 2018, a silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the coc ...
-derived sericin
Sericin is a protein created by ''Bombyx mori'' (silkworms) in the production of silk. Silk is a fibre produced by the silkworm in production of its Pupa#Cocoon, cocoon. It consists mainly of two proteins, fibroin and sericin. Silk consists of ...
hydrogel
A hydrogel is a crosslinked hydrophilic polymer that does not dissolve in water. They are highly absorbent yet maintain well defined structures. These properties underpin several applications, especially in the biomedical area. Many hydrogels ar ...
dressing was undergoing research, the material was shown to prevent scar formation.
References
External links
WebMd.com: Skin Scars Directory
American Academy of Dermatology: What is a scar?
{{Authority control
Healing
Skin conditions resulting from physical factors