Acne mechanica is an

acneiform eruption Acneiform eruptions are a group of dermatoses including acne vulgaris, rosacea, folliculitis, and perioral dermatitis. Restated, acneiform eruptions are follicular eruptions characterized by papules and pustules resembling acne.James, William; Be ...

that has been observed after repetitive

physical trauma 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, or ...

to the skin such as rubbing, occurring from clothing (belts and straps) or

sports equipment Sports equipment, sporting equipment, also called sporting goods, are the tools, materials, apparel, and gear used to compete in a sport and varies depending on the sport. The equipment ranges from balls, nets, and protective gear like helmets. ...

(football helmets and

shoulder pads Shoulder pads may refer to: * Shoulder pads (fashion) * Shoulder pads (sport), particularly gridiron football {{disambiguation ...

).Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). Page 685. McGraw-Hill. . In addition to those mechanisms, the skin not getting enough exposure to air also contributes to the formation of acne mechanica. It is often mistaken as a

rash A rash is a change of the human skin which affects its color, appearance, or texture. A rash may be localized in one part of the body, or affect all the skin. Rashes may cause the skin to change color, itch, become warm, bumpy, chapped, dry, c ...

that forms on sweaty skin that is constantly being rubbed, but in reality, it is a breakout of acne mechanica. The term "acne" itself describes the occurrence in which hair follicles (also known as pores) in the skin get clogged by oil, dead skin cells, dirt and

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

, or cosmetic products and create a pimple. Pimples can vary in type, size, and shape, but the sole basis of them occurring is the same - the oil gland in the pore becomes clogged and sometimes infected, which creates pus in order to fight the infection and subsequently causes the development of swollen, red

lesions 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 ...

on the skin.

Signs and symptoms

The signs and symptoms at an early stage are harder to be seen. At first look, acne mechanica seems very similar to any other type of

acne Acne, also known as ''acne vulgaris'', is a long-term skin condition that occurs when dead skin cells and oil from the skin clog hair follicles. Typical features of the condition include blackheads or whiteheads, pimples, oily skin, and ...

. However, it differs in how it is caused. A lot of acne has to do with hormones, the amount of oil production in the skin, and genetic predispositions. Acne mechanica specifically refers to the skin irritation that is formed by excess pressure, heat, and rubbing against the skin. When the skin is constantly rubbed, it initially becomes rough and then starts to develop acne-like bumps with continuing irritation like sweating or more friction. If the skin continues to be irritated for a longer period of time, a more serious acne lesion develops that grows in size and redness. They appear as small, red tender bumps called

papules 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 ...

. There may be a combination of whiteheads and

blackhead A comedo is a clogged hair follicle (pore) in the skin. Keratin (skin debris) combines with oil to block the follicle. A comedo can be open (blackhead) or closed by skin (whitehead) and occur with or without acne. The word "comedo" comes from the ...

s that also appear around the area affected, the difference being that whiteheads are closed and clogged pores whereas blackheads are also clogged but open pores. The symptoms may vary also depending on a person's skin type; overly oily or dry skin can cause a number of symptoms that heighten the possibility for acne mechanica to develop.

Cause

Repetitive rubbing of the skin, in instances such as backpack strings rubbing on your shoulders or helmet straps rubbing on your chin are actions that can irritate the skin and cause acne mechanica. Acne mechanica is a specific type of acne that is caused by

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of ...

, heat, and/or

pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country a ...

on the skin. Especially occurs when the skin is not exposed to air. It is commonly found in athletes because sweaty, constantly rubbed skin by a tight uniform, for example, can result in a

. What may look like a rash is actually acne mechanica. Another common area for acne mechanica to show up is on the sides of your face where you hold your cell phone, especially with the added bacteria it carries on it. There are some people who are more prone to develop acne mechanica. The biggest group of people affected by this type of acne are teenagers and young adults in their twenties who already experience issues with acne on their back, shoulders, and buttocks. Other people who have a type of acne commonly described as "sandpaper acne," which is characterized as small but rough acne lesions that are not very visible but feel like

sandpaper upright=1.35, Sheets of sandpaper with different grit sizes (40 (coarse), 80, 150, 240, 600 (fine)). Sandpaper and glasspaper are names used for a type of coated abrasive that consists of sheets of paper or cloth with abrasive material glued to ...

to the touch, also are more prone to developing acne mechanica.

Mechanism

Acne mechanica specifically is triggered by both mechanical and heat stress on the skin working together to cause this

irritation Irritation, in biology and physiology, is a state of inflammation or painful reaction to allergy or cell-lining damage. A stimulus or agent which induces the state of irritation is an irritant. Irritants are typically thought of as chemical age ...

. The skin that is exposed to these stressors initially develops a harder surface to protect itself, but if the skin is continually dealing with this pressure, it gets irritated and forms a rash. At this point, it gets qualified as acne mechanica. When you are in a hot

climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologi ...

or are working out and your body temperature rises, the heat causes the pores in your skin to open up. The dilation of the pores makes it easier for

, oil, and dead skin cells to collect in the pores and clog them. Every pore in your body has a tiny

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 ...

, and the blockage causes the hair follicle to become irritated and inflamed, which ends up forming pimples; specifically acne mechanica.

White blood cells White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from mult ...

flood the area of

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 ...

, and once they die, they accumulate on the surface of the pore, causing what is known as a "whitehead". When people pop pimples, pus comes out, which has the dead white blood cells in it that originally came to diffuse the inflammation. Depending on the continuation of the stressors, the inflammatory pimples (also known as papules and pustules) can develop into nodules and

cysts A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubble) ...

, which are more severe forms of acne that are rooted deeper within the skin.

Diagnosis

Acne mechanica can be diagnosed by a

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 medica ...

via a

physical examination In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally consists of a series of questions about the pati ...

. In more extreme cases, a skin

biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a dise ...

is performed to examine the

pathology Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in ...

. Family and medical history are also looked at to see if the patient has a hereditary tendency to certain conditions that cause different types of acne, which may play a role in acne mechanica development. For example, if a patient's parents had acne, there is a very strong probability they will also have similar issues. The issues can range from things like overproducing dead skin cells or the pores having a higher tendency to clog.

Treatment

Acne mechanica has no direct cure, however, there are preventive measures that can be taken to minimize its breakouts. The most obvious solution to prevent extra rubbing or heat entrapment on the surface of the skin is to wear either loose-fitting clothes or wearing clothes made out of more breathable fabrics, especially during exercising, playing sports, or when performing physical activities such as hiking. Loose clothes will not rub as much and create the mechanical stress on the skin. Instead of wearing clothes made out of

polyester Polyester is a category of polymers that contain the ester functional group in every repeat unit of their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include natura ...

and

rayon Rayon is a semi-synthetic fiber, made from natural sources of regenerated cellulose, such as wood and related agricultural products. It has the same molecular structure as cellulose. It is also called viscose. Many types and grades of viscose ...

, choosing

cotton Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor pe ...

materials will help relieve the heat stress on the skin and not trap sweat in the pores. Taking showers immediately after any form of physical exercise will also help keep the skin as clean as possible. Keeping up with a skin care regimen so the skin is moisturized helps as well. Using skin care products specifically with

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 Substa ...

benzoyl peroxide Benzoyl peroxide is a chemical compound (specifically, an organic peroxide) with structural formula , often abbreviated as (BzO)2. In terms of its structure, the molecule can be described as two benzoyl (, Bz) groups connected by a peroxide ( ...

help exfoliate the skin in a gentle manner and get rid of bacteria. Both of these chemicals in a facial

cleanser The term cleanser refers to a product that cleans or removes dirt or other substances. A cleanser could be a detergent, and there are many types of cleansers that are produced with a specific objective or focus. For instance a degreaser or carbur ...

may create a tingling sensation on people with extremely sensitive skin. Other topical ointments can be used once consulted with a dermatologist.

Prognosis

Long term effects of acne mechanica include potential

scarring A scar (or scar tissue) is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a na ...

and skin discoloration at the area of the acne lesion if rubbing of the skin continues. It is not a lethal condition and the acne will clear up on its own once the heat and pressure stressors are avoided and if the skin is kept clean so the pores do not continue to become clogged.

Epidemiology

Acne mechanica is most prevalent among athletes, soldiers in warm climates, teenagers and young adults. The athletes and soldiers can get rashes from their equipment and uniforms constantly rubbing their skin while sweating, which turn into acne mechanica lesions. Men tend to be more prone to develop acne mechanica because they produce more oil (also known as sebum) in their glands, even though their glands are actually smaller than women's. This is also a reason why men's acne tends to remain a problem for longer once its developed. Acne in general is

hereditary 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 informa ...

from parents to child, so

genetics Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinian friar work ...

play a factor as well. People who already have acne and have a problematic skin type that tends to create clogged pores are more likely to develop acne mechanica as well.

Research Directions

Although not exactly having to do with acne mechanica and the heat or pressure stressors that cause it, there is still not a lot of research relating to different organ's health relating to acne appearing on different areas of the body and face. A correlation between the two could be explored in future studies.

References

{{reflist Acneiform eruptions