Acne vulgaris
Overview
Acne vulgaris is a common human skin
Human skin
The human skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system. The skin has multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organs. Human skin is similar to that of most other mammals,...

 disease, characterized by areas of skin with seborrhea (scaly red skin), comedones (blackheads and whiteheads), papules (pinheads), pustules (pimples), Nodules (large papules) and possibly scarring. Acne affects mostly skin with the densest population of sebaceous follicles; these areas include the face, the upper part of the chest, and the back.
Encyclopedia
Acne vulgaris is a common human skin
Human skin
The human skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system. The skin has multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organs. Human skin is similar to that of most other mammals,...

 disease, characterized by areas of skin with seborrhea (scaly red skin), comedones (blackheads and whiteheads), papules (pinheads), pustules (pimples), Nodules (large papules) and possibly scarring. Acne affects mostly skin with the densest population of sebaceous follicles; these areas include the face, the upper part of the chest, and the back. Severe acne is inflammatory
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

, but acne can also manifest in noninflammatory forms. The lesions are caused by changes in pilosebaceous units, skin structures consisting of a hair follicle
Hair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....

 and its associated sebaceous gland
Sebaceous gland
The sebaceous glands are microscopic glands in the skin that secrete an oily/waxy matter, called sebum, to lubricate and waterproof the skin and hair of mammals...

, changes that require androgen
Androgen
Androgen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...

 stimulation.

Acne occurs most commonly during adolescence
Adolescence
Adolescence is a transitional stage of physical and mental human development generally occurring between puberty and legal adulthood , but largely characterized as beginning and ending with the teenage stage...

, and often continues into adulthood. In adolescence, acne is usually caused by an increase in testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...

, which people of both genders accrue during puberty.
For most people, acne diminishes over time and tends to disappear — or at the very least decrease — after one reaches one's early twenties. There is, however, no way to predict how long it will take to disappear entirely, and some individuals will carry this condition well into their thirties, forties, and beyond.

Some of the large nodules were previously called "cyst
Cyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...

s" and the term nodulocystic has been used to describe severe cases of inflammatory acne. The "cysts," or boils that accompany cystic acne, can appear on the buttocks, groin, and armpit area, and anywhere else where sweat collects in hair follicles and perspiration ducts. Cystic acne affects deeper skin tissue than does common acne.

Aside from scarring, its main effects are psychological, such as reduced self-esteem
Self-esteem
Self-esteem is a term in psychology to reflect a person's overall evaluation or appraisal of his or her own worth. Self-esteem encompasses beliefs and emotions such as triumph, despair, pride and shame: some would distinguish how 'the self-concept is what we think about the self; self-esteem, the...

 and in very extreme cases, depression
Clinical depression
Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...

 or suicide
Suicide
Suicide is the act of intentionally causing one's own death. Suicide is often committed out of despair or attributed to some underlying mental disorder, such as depression, bipolar disorder, schizophrenia, alcoholism, or drug abuse...

. Acne usually appears during adolescence
Adolescence
Adolescence is a transitional stage of physical and mental human development generally occurring between puberty and legal adulthood , but largely characterized as beginning and ending with the teenage stage...

, when people already tend to be most socially insecure. Early and aggressive treatment is therefore advocated by some to lessen the overall long-term impact to individuals.

Terminology

The term acne comes from a corruption of the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 ἀκμή (akmē), literally "point, edge", but in the sense of a "skin eruption" in the writings of Aëtius Amidenus
Aëtius Amidenus
Aëtius of Amida was a Byzantine physician and medical writer, particularly distinguished by the extent of his erudition. Historians are not agreed about his exact date...

. Used by itself, the term "acne" refers to the presence of pustules and papule
Papule
A papule is a circumscribed, solid elevation of skin with no visible fluid, varying in size from a pinhead to 1 cm.With regard to the quote "...varying in size from a pinhead to 1cm," depending on which text is referenced, some authors state the cutoff between a papule and a plaque as 0.5cm,...

s. The most common form of acne is known as acne vulgaris, meaning "common acne". Many teenagers get this type of acne. Use of the term "acne vulgaris" implies the presence of comedones.

The term "acne rosea" is a synonym for rosacea
Rosacea
Rosacea is a chronic condition characterized by facial erythema . Pimples are sometimes included as part of the definition. Unless it affects the eyes, it is typically a harmless cosmetic condition...

, however some individuals may have almost no acne comedones associated with their rosacea and prefer therefore the term rosacea. Chloracne
Chloracne
Chloracne is an acne-like eruption of blackheads, cysts, and pustules associated with over-exposure to certain halogenated aromatic compounds, such as chlorinated dioxins and dibenzofurans...

 is associated with exposure to polyhalogenated compound
Polyhalogenated compound
Polyhalogenated compounds are any compounds with multiple substitutions of halogens. They are of particular interest and importance because halogens generally are highly reactive and also bioaccumulate in humans, and comprise a superset of which has many toxic and carcinogenic industrial...

s.

Signs and symptoms

Typical features of acne include: seborrhea (scaly red skin), comedones (blackheads and whiteheads), papules (pinheads), pustules (pimples), nodules (large papules) and, possibly scarring. It presents somewhat differently in people with dark skin.

Scars

Acne scar
Scar
Scars are areas of fibrous tissue that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in...

s are the result of inflammation within the dermis brought on by acne. The scar is created by the wound trying to heal itself resulting in too much collagen in one spot.

Physical acne scars are often referred to as "Icepick" scars. This is because the scars tend to cause an indentation in the skin's surface. There are a range of treatments available. Although quite rare, the medical condition Atrophia Maculosa Varioliformis Cutis
Atrophia Maculosa Varioliformis Cutis
Atrophia Maculosa Varioliformis Cutis is a condition involving spontaneous scarring, specifically depressed scars on the face occurring over a period of months to years. It appears to only affect children and young adults, is considered to be quite rare, normally occurs on the cheeks, temple...

 also results in "acne-like" depressed scars on the face.
  • Ice pick scars: Deep pits, that are the most common and a classic sign of acne scarring.
  • Box car scars: Angular scars that usually occur on the temple and cheeks, and can be either superficial or deep, these are similar to chickenpox
    Chickenpox
    Chickenpox or chicken pox is a highly contagious illness caused by primary infection with varicella zoster virus . It usually starts with vesicular skin rash mainly on the body and head rather than at the periphery and becomes itchy, raw pockmarks, which mostly heal without scarring...

     scars.
  • Rolling scars: Scars that give the skin a wave-like appearance.
  • Hypertrophic scars: Thickened, or keloid
    Keloid
    A keloid is a type of scar, which depending on its maturity, is composed mainly of either type III or type I collagen. It is a result of an overgrowth of granulation tissue at the site of a healed skin injury which is then slowly replaced by collagen type 1...

     scars.

Pigmentation

Pigmented scars is a slightly misleading term, as it suggests a change in the skin's pigmentation and that they are true scars; however, neither is true. Pigmented scars are usually the result of nodular or cystic acne (the painful 'bumps' lying under the skin). They often leave behind an inflamed red mark. Often, the pigmentation scars can be avoided simply by avoiding aggravation of the nodule or cyst. Pigmentation scars nearly always fade with time taking between three months to two years to do so, although can last forever if untreated.

Cause

Acne develops as a result of blockages in follicles
Hair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....

. Hyperkeratinization
Hyperkeratinization
Hyperkeratinization is a disorder of the cells lining the inside of a hair follicle. It is the normal function of these cells to detach or slough off from the skin lining at normal intervals. The dead cells are then forced out of the follicle...

 and formation of a plug of keratin
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...

 and sebum (a microcomedo
Comedo
Comedo may refer to:*Blackhead *Whitehead : non inflamed pore blocked with sebum, a symptom of acne vulgaris...

) is the earliest change. Enlargement of sebaceous glands and an increase in sebum production occur with increased androgen
Androgen
Androgen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...

 (DHEA-S
Dehydroepiandrosterone
5-Dehydroepiandrosterone is a 19-carbon endogenous steroid hormone. It is the major secretory steroidal product of the adrenal glands and is also produced by the gonads and the brain. DHEA is the most abundant circulating steroid in humans....

) production at adrenarche
Adrenarche
Adrenarche is an early sexual maturation stage in some higher primates that in humans typically occurs at around 6 to 8 years of age. During adrenarche the adrenal cortex secretes increased levels of androgens such as DHEA and DHEAS, but without increased cortisol levels. Adrenarche is the result...

. The microcomedo may enlarge to form an open comedone (blackhead
Blackhead
A blackhead is a yellow or blackish bump or plug on the skin. A blackhead is a type of acne vulgaris. Contrary to the common belief that it is caused by poor hygiene, blackheads are caused by excess oils that have accumulated in the sebaceous gland's duct...

) or closed comedone (milia). Comedones are the direct result of sebaceous gland
Sebaceous gland
The sebaceous glands are microscopic glands in the skin that secrete an oily/waxy matter, called sebum, to lubricate and waterproof the skin and hair of mammals...

s' becoming clogged with sebum, a naturally occurring oil, and dead skin cells. In these conditions, the naturally occurring largely commensal bacterium Propionibacterium acnes
Propionibacterium acnes
Propionibacterium acnes is a relatively slow growing, typically aerotolerant anaerobic gram positive bacterium that is linked to the skin condition acne; it can also cause chronic blepharitis and endophthalmitis, the latter particularly following intraocular surgery...

can cause inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

, leading to inflammatory lesions (papule
Papule
A papule is a circumscribed, solid elevation of skin with no visible fluid, varying in size from a pinhead to 1 cm.With regard to the quote "...varying in size from a pinhead to 1cm," depending on which text is referenced, some authors state the cutoff between a papule and a plaque as 0.5cm,...

s, infected pustules, or nodules) in the dermis
Dermis
The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...

 around the microcomedo or comedone, which results in redness and may result in scar
Scar
Scars are areas of fibrous tissue that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in...

ring or hyperpigmentation
Hyperpigmentation
In dermatology, hyperpigmentation is the darkening of an area of skin or nails caused by increased melanin.-Causes:Hyperpigmentation may be caused by sun damage, inflammation, or other skin injuries, including those related to acne vulgaris...

.

Hormonal

Hormonal activity, such as menstrual cycles
Menstruation
Menstruation is the shedding of the uterine lining . It occurs on a regular basis in sexually reproductive-age females of certain mammal species. This article focuses on human menstruation.-Overview:...

 and puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as 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 male sex hormones called androgens cause the follicular glands to grow larger and make more sebum. Use of anabolic steroid
Anabolic steroid
Anabolic steroids, technically known as anabolic-androgen steroids or colloquially simply as "steroids", are drugs that mimic the effects of testosterone and dihydrotestosterone in the body. They increase protein synthesis within cells, which results in the buildup of cellular tissue ,...

s may have a similar effect.
Several hormone
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

s have been linked to acne: the androgens testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...

, dihydrotestosterone
Dihydrotestosterone
Dihydrotestosterone is an androgen or male sex hormone. The enzyme 5α-reductase synthesises DHT in the prostate, testes, hair follicles, and adrenal glands...

 (DHT) and dehydroepiandrosterone sulfate
Dehydroepiandrosterone
5-Dehydroepiandrosterone is a 19-carbon endogenous steroid hormone. It is the major secretory steroidal product of the adrenal glands and is also produced by the gonads and the brain. DHEA is the most abundant circulating steroid in humans....

 (DHEAS), as well as insulin-like growth factor 1
Insulin-like growth factor 1
Insulin-like growth factor 1 also known as somatomedin C is a protein that in humans is encoded by the IGF1 gene. IGF-1 has also been referred to as a "sulfation factor" and its effects were termed "nonsuppressible insulin-like activity" in the 1970s.IGF-1 is a hormone similar in molecular...

 (IGF-I).

Development of acne vulgaris in later years is uncommon, although this is the age group for rosacea
Rosacea
Rosacea is a chronic condition characterized by facial erythema . Pimples are sometimes included as part of the definition. Unless it affects the eyes, it is typically a harmless cosmetic condition...

, which may have similar appearances. True acne vulgaris in adult women may be a feature of an underlying condition such as pregnancy and disorders such as polycystic ovary syndrome
Polycystic ovary syndrome
Polycystic ovary syndrome is one of the most common female endocrine disorders. PCOS is a complex, heterogeneous disorder of uncertain aetiology, but there is strong evidence that it can to a large degree be classified as a genetic disease....

 or the rare Cushing's syndrome
Cushing's syndrome
Cushing's syndrome is a hormone disorder caused by high levels of cortisol in the blood. This can be caused by taking glucocorticoid drugs, or by tumors that produce cortisol or adrenocorticotropic hormone or CRH...

. Menopause-associated acne occurs as production of the natural anti-acne ovarian hormone estradiol
Estradiol
Estradiol is a sex hormone. Estradiol is abbreviated E2 as it has 2 hydroxyl groups in its molecular structure. Estrone has 1 and estriol has 3 . Estradiol is about 10 times as potent as estrone and about 80 times as potent as estriol in its estrogenic effect...

 fails at menopause. The lack of estradiol also causes thinning hair, hot flushes, thin skin, wrinkles, vaginal dryness, and predisposes to osteopenia and osteoporosis as well as triggering acne (known as acne climacterica in this situation).

Genetic

The tendency to develop acne runs in families. For example, school aged boys with acne often have other members in their family with acne. A family history of acne is associated with an earlier occurrence of acne and an increased number of retentional acne lesions.

Psychological

While the connection between acne and stress has been debated, scientific research indicates that "increased acne severity" is "significantly associated with increased stress levels." The National Institutes of Health (USA) list stress as a factor that "can cause an acne flare." A study of adolescents in Singapore "observed a statistically significant positive correlation […] between stress levels and severity of acne." It is also not clear whether acne causes stress and thus perpetuates itself to some extent.

Infectious

Propionibacterium acnes (P. acnes)
Propionibacterium acnes
Propionibacterium acnes is a relatively slow growing, typically aerotolerant anaerobic gram positive bacterium that is linked to the skin condition acne; it can also cause chronic blepharitis and endophthalmitis, the latter particularly following intraocular surgery...

is the anaerobic bacterium species that is widely concluded to cause acne, though Staphylococcus epidermidis
Staphylococcus epidermidis
Staphylococcus epidermidis is one of thirty-three known species belonging to the genus Staphylococcus. It is part of human skin flora, and consequently part of human flora. It can also be found in the mucous membranes and in animals. Due to contamination, it is probably the most common species...

 has been universally discovered to play some role since normal pores appear colonized only by P.acnes. Regardless, there are specific clonal sub-strains of P.acnes associated with normal skin health and others with long-term acne problems. It is as yet inconclusive whether any of these undesirable strains evolve on-site in the adverse conditions or are all pathogenically acquired, or possibly either depending on the individual patient. These strains either have the capability of changing, perpetuating, or adapting to, the abnormal cycle of inflammation, oil production, and inadequate sloughing activities of acne pores. At least one particularly virulent strain, though, has been circulating around Europe for at least 87 years. In vitro, resistance of P. acnes to commonly used antibiotics has been increasing, as well.

Diet

A high glycemic load
Glycemic load
The glycemic load is a ranking system for carbohydrate content in food portions based on their glycemic index and a standardized portion size of 100g. Glycemic load or GL combines both the quality and quantity of carbohydrate in one number. It is the best way to predict blood glucose values of...

 diet is associated with worsening acne. There is also an association between the consumption of milk and the rate and severity of acne. Other associations such as chocolate
Chocolate
Chocolate is a raw or processed food produced from the seed of the tropical Theobroma cacao tree. Cacao has been cultivated for at least three millennia in Mexico, Central and South America. Its earliest documented use is around 1100 BC...

 and salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

 are not supported by the evidence. However, products with these ingredients often contain a high glycemic load.

Diagnosis

There are multiple grading scales for grading the severity of acne vulgaris, three of these being:
  • Leeds acne grading technique: Counts and categorises lesions into inflammatory and non-inflammatory (ranges from 0–10.0).
  • Cook's acne grading scale: Uses photographs to grade severity from 0 to 8 (0 being the least severe and 8 being the most severe).
  • Pillsbury scale: Simply classifies the severity of the acne from 1 (least severe) to 4 (most severe).

Management

Many different treatments exist for acne including benzoyl peroxide
Benzoyl peroxide
Benzoyl peroxide is an organic compound in the peroxide family. It consists of two benzoyl groups bridged by a peroxide link. Its structural formula is [C6H5C]2O2. It is one of the most important organic peroxides in terms of applications and the scale of its production...

, antibiotics, retinoids, antiseborrheic medications, anti-androgen medications, hormonal
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

 treatments, salicylic acid
Salicylic acid
Salicylic acid is a monohydroxybenzoic acid, a type of phenolic acid and a beta hydroxy acid. This colorless crystalline organic acid is widely used in organic synthesis and functions as a plant hormone. It is derived from the metabolism of salicin...

, alpha hydroxy acid
Alpha hydroxy acid
α-Hydroxy acids, or alpha hydroxy acids , are a class of chemical compounds that consist of a carboxylic acid substituted with a hydroxyl group on the adjacent carbon. They may be either naturally occurring or synthetic. AHAs are well-known for their use in the cosmetics industry...

, azelaic acid
Azelaic acid
Azelaic acid is an organic compound with the formula 72. This saturated dicarboxylic acid exists as a white powder. It is found in wheat, rye, and barley. It is a component of a number of hair and skin conditioners.-Production:...

, nicotinamide
Nicotinamide
Nicotinamide, also known as niacinamide and nicotinic acid amide, is the amide of nicotinic acid . Nicotinamide is a water-soluble vitamin and is part of the vitamin B group...

, and keratolytic soaps. They are believed to work in at least 4 different ways, including: normalising shedding into the pore to prevent blockage, killing Propionibacterium acnes
Propionibacterium acnes
Propionibacterium acnes is a relatively slow growing, typically aerotolerant anaerobic gram positive bacterium that is linked to the skin condition acne; it can also cause chronic blepharitis and endophthalmitis, the latter particularly following intraocular surgery...

, anti-inflammatory effects, hormonal manipulation.

Exercise

Increased blood flow following exercise assists the maintenance of skin cells as it brings in oxygen and nutrients while removing waste. A secondary effect of exercise on acne is that it can reduce stress.

Medications

Benzoyl peroxide
Benzoyl peroxide
Benzoyl peroxide
Benzoyl peroxide is an organic compound in the peroxide family. It consists of two benzoyl groups bridged by a peroxide link. Its structural formula is [C6H5C]2O2. It is one of the most important organic peroxides in terms of applications and the scale of its production...

 is a first-line treatment for mild and moderate acne vulgaris due to its effectiveness and mild side-effects (primarily an irritant dermatitis
Dermatitis
-Etymology:Dermatitis derives from Greek derma "skin" + -itis "inflammation" and genetic disorder.-Terminology:There are several different types of dermatitis. The different kinds usually have in common an allergic reaction to specific allergens. The term may describe eczema, which is also called...

). It works against the "P. acnes" bacterium, and normally causes just dryness of the skin, slight redness, and occasional peeling when side-effects occur. This topical does increase sensitivity to the sun as indicated on the package, so sunscreen should be used during the treatment to prevent sunburn. Benzoyl peroxide has been found to be nearly as effective as antibiotics with all concentrations 2.5%, 5.0%, and 10% equally effective. Unlike antibiotics, benzoyl peroxide does not appear to generate bacterial resistance.

Antibiotics
Antibiotics are reserved for more severe cases. With increasing resistance of P. acnes worldwide, they are becoming less effective. Commonly used antibiotics, either applied topically or taken orally, include erythromycin
Erythromycin
Erythromycin is a macrolide antibiotic that has an antimicrobial spectrum similar to or slightly wider than that of penicillin, and is often used for people who have an allergy to penicillins. For respiratory tract infections, it has better coverage of atypical organisms, including mycoplasma and...

, clindamycin
Clindamycin
Clindamycin rINN is a lincosamide antibiotic. It is usually used to treat infections with anaerobic bacteria but can also be used to treat some protozoal diseases, such as malaria...

, and tetracyclines such as minocycline
Minocycline
Minocycline is a broad-spectrum tetracycline antibiotic, and has a broader spectrum than the other members of the group. It is a bacteriostatic antibiotic, classified as a long-acting type...

.

Hormones
In females, acne can be improved with hormonal
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

 treatments. The common combined estrogen
Estrogen
Estrogens , oestrogens , or œstrogens, are a group of compounds named for their importance in the estrous cycle of humans and other animals. They are the primary female sex hormones. Natural estrogens are steroid hormones, while some synthetic ones are non-steroidal...

/progestogen
Progestagen
Progestogens are a group of hormones including progesterone.The progestogens are one of the five major classes of steroid hormones, in addition to the estrogens, androgens, mineralocorticoids, and glucocorticoids. All progestogens are characterized by their basic 21-carbon skeleton, called a...

 methods of hormonal contraception
Hormonal contraception
Hormonal contraception refers to birth control methods that act on the endocrine system. Almost all methods are composed of steroid hormones, although in India one selective estrogen receptor modulator is marketed as a contraceptive. The original hormonal method—the combined oral contraceptive...

 have some effect, but the antiandrogen
Antiandrogen
Antiandrogens, or androgen antagonists, first discovered in the 1960s, prevent androgens from expressing their biological effects on responsive tissues. Antiandrogens alter the androgen pathway by blocking the appropriate receptors, competing for binding sites on the cell's surface, or affecting...

 cyproterone
Cyproterone
Cyproterone acetate is an antiandrogen...

 in combination with an oestrogen (Diane 35) is particularly effective at reducing androgenic hormone levels. Diane-35 is not available in the USA, but a newer oral contraceptive containing the progestin drospirenone
Drospirenone
Drospirenone is an anti-androgenic synthetic progestin that is typically used in birth control. There have been concerns raised regarding its safety and is thus not recommended as a first line agent.- Medical uses :...

 is now available with fewer side-effects than Diane 35 / Dianette. Both can be used where blood tests show abnormally high levels of androgen
Androgen
Androgen, also called androgenic hormone or testoid, is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of male characteristics in vertebrates by binding to androgen receptors...

s, but are effective even when this is not the case. Along with this, treatment with low-dose spironolactone can have anti-androgenetic properties, especially in patients with polycystic ovarian syndrome.

Topical retinoids
A group of medications for normalizing the follicle cell life-cycle are topical
Topical
In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, anus, throat, eyes and ears.Many topical medications are epicutaneous, meaning that they are applied directly to the skin...

 retinoids such as tretinoin
Tretinoin
Tretinoin is the acid form of vitamin A and is also known as all-trans retinoic acid or ATRA. It is a drug commonly used to treat acne vulgaris and keratosis pilaris. It is available as a cream or gel...

 (Retin-A), adapalene
Adapalene
Adapalene is a third-generation topical retinoid primarily used in the treatment of mild-moderate acne and is also used to treat keratosis pilaris as well as other skin conditions.- History :Adapalene was approved in 1996 by the U.S...

 (Differin), and tazarotene
Tazarotene
Tazarotene is a prescription topical retinoid sold as a cream or gel. This medication is approved for treatment of psoriasis, acne, and sun damaged skin...

 (Tazorac). Like isotretinoin, they are related to vitamin A
Vitamin A
Vitamin A is a vitamin that is needed by the retina of the eye in the form of a specific metabolite, the light-absorbing molecule retinal, that is necessary for both low-light and color vision...

, but they are administered as topicals and, in general, have much milder side-effects. They can, however, cause significant irritation of the skin. The retinoids appear to influence the cell creation and death life-cycle of cells in the follicle lining. This helps prevent the hyperkeratinization
Hyperkeratinization
Hyperkeratinization is a disorder of the cells lining the inside of a hair follicle. It is the normal function of these cells to detach or slough off from the skin lining at normal intervals. The dead cells are then forced out of the follicle...

 of these cells that can create a blockage. Retinol
Retinol
Retinol is one of the animal forms of vitamin A. It is a diterpenoid and an alcohol. It is convertible to other forms of vitamin A, and the retinyl ester derivative of the alcohol serves as the storage form of the vitamin in animals....

, a form of vitamin A, has similar, but milder, effects and is used in many over-the-counter moisturizers and other topical products. Effective topical retinoids have been in use for over 30 years, but are available only on prescription, so are not as widely used as the other topical treatments. Topical retinoids often cause an initial flare-up of acne and facial flushing
Flushing (physiology)
For a person to flush is to become markedly red in the face and often other areas of the skin, from various physiological conditions. Flushing is generally distinguished, despite a close physiological relation between them, from blushing, which is milder, generally restricted to the face, cheeks or...

.

Oral retinoids
A daily oral intake of vitamin A derivative isotretinoin
Isotretinoin
Isotretinoin, INN, is a medication used mostly for cystic acne. It was first developed for brain, pancreatic and other cancers. It is used to treat harlequin-type ichthyosis, a usually lethal skin disease, and lamellar ichthyosis. Its effects are systemic and nonselective...

 (marketed as Roaccutane, Accutane, Amnesteem, Sotret, Claravis, Clarus) over a period of 4–6 months can cause long-term resolution or reduction of acne. It is believed that isotretinoin works primarily by reducing the secretion of oils from the glands, however some studies suggest that it affects other acne-related factors as well. Isotretinoin has been shown to be very effective in treating severe acne and can either improve or clear well over 80% of patients. The drug has a much longer effect than anti-bacterial treatments and will often cure acne for good. The treatment requires close medical supervision by a dermatologist because the drug has many known side-effects
Adverse effect (medicine)
In medicine, an adverse effect is a harmful and undesired effect resulting from a medication or other intervention such as surgery.An adverse effect may be termed a "side effect", when judged to be secondary to a main or therapeutic effect. If it results from an unsuitable or incorrect dosage or...

 (many of which can be severe). About 25% of patients may relapse after one treatment. In those cases, a second treatment for another 4–6 months may be indicated to obtain desired results. It is often recommended that one let a few months pass between the two treatments, because the condition can actually improve somewhat in the time after stopping the treatment and waiting a few months also gives the body a chance to recover. On occasion, a third or even a fourth course is used, but the benefits are often less substantial. The most common side-effects are dry skin and occasional nosebleeds (secondary to dry nasal mucosa). Oral retinoids also often cause an initial flare-up of acne within a month or so, which can be severe. There are reports that the drug has damaged the liver of patients. For this reason, it is recommended that patients have blood samples taken and examined before and during treatment. In some cases, treatment is terminated or reduced due to elevated liver enzymes in the blood, which might be related to liver damage. Others claim that the reports of permanent damage to the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...

 are unsubstantiated, and routine testing is considered unnecessary by some dermatologists. Blood triglycerides also need to be monitored. However, routine testing are part of the official guidelines for the use of the drug in many countries. Some press reports suggest that isotretinoin may cause depression
Clinical depression
Major depressive disorder is a mental disorder characterized by an all-encompassing low mood accompanied by low self-esteem, and by loss of interest or pleasure in normally enjoyable activities...

, but, as of September 2005, there is no agreement in the medical literature as to the risk. The drug also causes birth defects if women become pregnant while taking it or take it while pregnant. For this reason, female patients are required to use two separate forms of birth control
Birth control
Birth control is an umbrella term for several techniques and methods used to prevent fertilization or to interrupt pregnancy at various stages. Birth control techniques and methods include contraception , contragestion and abortion...

 or vow abstinence
Abstinence
Abstinence is a voluntary restraint from indulging in bodily activities that are widely experienced as giving pleasure. Most frequently, the term refers to sexual abstinence, or abstention from alcohol or food. The practice can arise from religious prohibitions or practical...

 while on the drug. Because of this, the drug is supposed to be given to females as a last resort after milder treatments have proven insufficient. Restrictive rules (see iPledge
IPLEDGE
The iPLEDGE program is a mandatory distribution program in the United States for isotretinoin , intended to prevent the use of the drug during pregnancy due to the high risk of birth defects...

 program) for use were put into force in the USA beginning in March 2006 to prevent misuse, causing occasioned widespread editorial comment.

Anti-inflammatories
Nicotinamide
Nicotinamide
Nicotinamide, also known as niacinamide and nicotinic acid amide, is the amide of nicotinic acid . Nicotinamide is a water-soluble vitamin and is part of the vitamin B group...

, (vitamin B3) used topically in the form of a gel, has been shown in a 1995 study to be of comparable efficacy to topical clindamycin used for comparison. The property of topical nicotinamide's benefit in treating acne seems to be its anti-inflammatory nature. It is also purported to result in increased synthesis of collagen, keratin, involucrin and flaggrin, and may also, according to a cosmetic company, be useful for reducing skin hyperpigmentation (acne scars), increasing skin moisture and reducing fine wrinkles.

Ibuprofen
Ibuprofen
Ibuprofen is a nonsteroidal anti-inflammatory drug used for relief of symptoms of arthritis, fever, as an analgesic , especially where there is an inflammatory component, and dysmenorrhea....

 in combination with tetracycline are used for some moderate acne cases for their anti-inflammatory effects.

Mandelic acid
Mandelic acid
Mandelic acid is an aromatic alpha hydroxy acid with the molecular formula C6H5CHCO2H. It is a white crystalline solid that is soluble in water and polar organic solvents. It is a useful precursor to various drugs...

 has been noted to be an effective topical treatment for mild to moderate acne. It is considered to be a gentler alternative to popular alpha hydroxy acids, such as glycolic acid
Glycolic acid
Glycolic acid is the smallest α-hydroxy acid . This colorless, odorless, and hygroscopic crystalline solid is highly soluble in water. It is used in various skin-care products. Glycolic acid is found in some sugar-crops...

 and lactic acid.

Dermabrasion

Dermabrasion
Dermabrasion
Dermabrasion is a surgical procedure that involves the controlled abrasion of the upper layers of the skin with sandpaper or other mechanical means. Nowadays it has become common to use CO2 or Erbium:YAG laser as well. The procedure requires a local anaesthetic...

 is a cosmetic
Beauty
Beauty is a characteristic of a person, animal, place, object, or idea that provides a perceptual experience of pleasure, meaning, or satisfaction. Beauty is studied as part of aesthetics, sociology, social psychology, and culture...

 medical procedure in which the surface of the skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

 is removed by abrasion (sanding).
It is used to remove sun-damaged skin and to remove or lessen scar
Scar
Scars are areas of fibrous tissue that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in...

s and dark spots on the skin. The procedure is very painful and usually requires a general anaesthetic
General anaesthetic
A general anaesthetic is a drug that brings about a reversible loss of consciousness. These drugs are generally administered by an anaesthesia provider to induce or maintain general anaesthesia to facilitate surgery...

 or "twilight anaesthesia", in which the patient is still partly conscious. Afterward, the skin is very red and raw-looking, and it takes several months for the skin to regrow and heal. Dermabrasion is useful for scar removal when the scar is raised above the surrounding skin, but is less effective with sunken scars.

In the past, dermabrasion was done using a small, sterilized, electric sander. In the past decade, it has become more common to use laser dermabrasion using CO2
Carbon dioxide laser
The carbon dioxide laser was one of the earliest gas lasers to be developed , and is still one of the most useful. Carbon dioxide lasers are the highest-power continuous wave lasers that are currently available...

, Er:YAG laser
Er:YAG laser
Er:YAG lasers are solid-state lasers whose lasing medium is erbium-doped yttrium aluminium garnet . Er:YAG lasers typically emit light with a wavelength of 2940 nm, which is infrared light. Unlike Nd:YAG lasers, the output of an Er:YAG laser is strongly absorbed by water because of atomic resonances...

 or a combination of both for the treatment of acne scars. Indications for CO2 laser treatment include previous non erythematous and non-proliferative hypertrophic scars, atrophic acne scars and burn scars. Laser dermabrasion is much easier to control, much easier to gauge, and is practically bloodless compared to classic dermabrasion.
Blue and red light

Light exposure has long been used as a short-term treatment for acne. Recently, visible light has been successfully employed to treat mild to moderate acne (phototherapy or deep penetrating light therapy) - in particular intense violet light (405–420 nm) generated by purpose-built fluorescent lighting, dichroic bulbs, LED
LEd
LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....

s or lasers. Used twice weekly, this has been shown to reduce the number of acne lesions by about 64%
and is even more effective when applied daily. The mechanism appears to be that a porphyrin
Porphyrin
Porphyrins are a group of organic compounds, many naturally occurring. One of the best-known porphyrins is heme, the pigment in red blood cells; heme is a cofactor of the protein hemoglobin. Porphyrins are heterocyclic macrocycles composed of four modified pyrrole subunits interconnected at...

 (Coproporphyrin III) produced within P. acnes generates free radicals when irradiated by 420 nm and shorter wavelengths of light.
Particularly when applied over several days, these free radicals ultimately kill the bacteria.
Since porphyrins are not otherwise present in skin, and no UV light is employed, it appears to be safe, and has been cleared for marketing by the U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 FDA
Food and Drug Administration
The Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...

.

It seems that the treatment works even better if used with a mixture of the violet light and red visible light (660 nanometer), resulting in a 76% reduction of lesions after three months of daily treatment for 80% of the patients; and overall clearance was similar or better than benzoyl peroxide. Unlike most of the other treatments, few if any negative side-effects are typically experienced, and the development of bacterial resistance to the treatment seems very unlikely. After treatment, clearance can be longer-lived than is typical with topical or oral antibiotic treatments; several months is not uncommon. The equipment or treatment, however, is relatively new and reasonably expensive to buy initially, although the total cost of ownership can be similar to many other treatment methods (such as the total cost of benzoyl peroxide, moisturizer, washes) over a couple of years of use.
Photodynamic therapy

In addition, basic science and clinical work by dermatologists Yoram Harth and Alan Shalita and others has produced evidence that intense blue/violet light (405–425 nanometer) can decrease the number of inflammatory acne lesion by 60–70% in four weeks of therapy, in particular, when the P. acnes is pretreated with delta-aminolevulinic acid (ALA), which increases the production of porphyrins. However this photodynamic therapy is controversial and not published in a peer-reviewed journal. A phase II trial, while it showed improvement occurred, failed to show improved response compared to the blue/violet light alone.
Laser treatment

Laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

 surgery has been in use for some time to reduce the scars left behind by acne, but research has been done on lasers for prevention of acne formation itself. The laser is used to produce one of the following effects:
  • to burn away the follicle sac from which the hair grows
  • to burn away the sebaceous gland, which produces the oil
  • to induce formation of oxygen
    Oxygen
    Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

     in the bacteria, killing them


Since lasers and intense pulsed light sources cause thermal damage to the skin, there are concerns that laser or intense pulsed light treatments for acne will induce hyperpigmented macules (spots) or cause long-term dryness of the skin.

The FDA has approved the use of a cosmetic laser for the treatment of acne. However, efficacy studies have used very small sample sizes for periods of six months or less, and have shown contradictory results. Also, laser treatment being relatively new, protocols remain subject to experimentation and revision, and treatment can be quite expensive. Also, some Smoothbeam laser devices had to be recalled due to coolant failure, which resulted in painful burn injuries to patients.

Surgery

For people with cystic acne, boils can be drained through surgical lancing
Incision and drainage
Incision and drainage and clinical lancing are minor surgical procedures to release pus or pressure built up under the skin, such as from an abscess, boil, or infected paranasal sinus...

.

Alternative medicine

  • Tea tree oil
    Tea tree oil
    Tea tree oil, or melaleuca oil, is a pale yellow colour to nearly clear essential oil with a fresh camphoraceous odor. It is taken from the leaves of the Melaleuca alternifolia, which is native to the northeast coast of New South Wales, Australia...

     (melaleuca oil) has been used with some success, where it is comparable to benzoyl peroxide but without excessive drying, kills P. acnes, and has been shown to be an effective anti-inflammatory in skin infections.
  • Aloe vera
    Aloe vera
    Aloe vera, pronounced , also known as the true aloe or medicinal aloe, is a species of succulent plant in the genus Aloe that is believed to have originated in the Sudan. Aloe vera grows in arid climates and is widely distributed in Africa, India, Nepal and other arid areas.The species is...

    : there are treatments for acne mentioned in Ayurveda
    Ayurveda
    Ayurveda or ayurvedic medicine is a system of traditional medicine native to India and a form of alternative medicine. In Sanskrit, words , meaning "longevity", and , meaning "knowledge" or "science". The earliest literature on Indian medical practice appeared during the Vedic period in India,...

     using herbs such as Aloe vera
    Aloe vera
    Aloe vera, pronounced , also known as the true aloe or medicinal aloe, is a species of succulent plant in the genus Aloe that is believed to have originated in the Sudan. Aloe vera grows in arid climates and is widely distributed in Africa, India, Nepal and other arid areas.The species is...

    , Neem
    Neem
    Azadirachta indica is a tree in the mahogany family Meliaceae. It is one of two species in the genus Azadirachta, and is native to India growing in tropical and semi-tropical regions. Its fruits and seeds are the source of neem oil...

    , Haldi (Turmeric)
    Turmeric
    Turmeric is a rhizomatous herbaceous perennial plant of the ginger family, Zingiberaceae. It is native to tropical South Asia and needs temperatures between 20 °C and 30 °C and a considerable amount of annual rainfall to thrive...

     and Papaya
    Papaya
    The papaya , papaw, or pawpaw is the fruit of the plant Carica papaya, the sole species in the genus Carica of the plant family Caricaceae...

    . However, scientific evidence for the cosmetic effectiveness of aloe vera is limited and when present is frequently contradictory.

Epidemiology

Acne affects 40 to 50 million people in the United States (16%), and approximately 3 to 5 million in Australia (23%). It affects people of all racial and ethnic groups.

History

  • Ancient Egypt
    Ancient Egypt
    Ancient Egypt was an ancient civilization of Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. Egyptian civilization coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh...

     and Ancient Greece
    Ancient Greece
    Ancient Greece is a civilization belonging to a period of Greek history that lasted from the Archaic period of the 8th to 6th centuries BC to the end of antiquity. Immediately following this period was the beginning of the Early Middle Ages and the Byzantine era. Included in Ancient Greece is the...

    : Sulfur
    Sulfur
    Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...

     is used to treat acne.
  • 1920s: Benzoyl peroxide
    Benzoyl peroxide
    Benzoyl peroxide is an organic compound in the peroxide family. It consists of two benzoyl groups bridged by a peroxide link. Its structural formula is [C6H5C]2O2. It is one of the most important organic peroxides in terms of applications and the scale of its production...

     is used as a medication to treat acne.
  • 1970s: Tretinoin
    Tretinoin
    Tretinoin is the acid form of vitamin A and is also known as all-trans retinoic acid or ATRA. It is a drug commonly used to treat acne vulgaris and keratosis pilaris. It is available as a cream or gel...

     (original Trade Name Retin A) was found effective for acne. This preceded the development of oral isotretinoin
    Isotretinoin
    Isotretinoin, INN, is a medication used mostly for cystic acne. It was first developed for brain, pancreatic and other cancers. It is used to treat harlequin-type ichthyosis, a usually lethal skin disease, and lamellar ichthyosis. Its effects are systemic and nonselective...

     (sold as Accutane and Roaccutane) in 1980. Also, antibiotics such as minocycline
    Minocycline
    Minocycline is a broad-spectrum tetracycline antibiotic, and has a broader spectrum than the other members of the group. It is a bacteriostatic antibiotic, classified as a long-acting type...

     are used as treatments for acne.
  • 1980s: Accutane
    Isotretinoin
    Isotretinoin, INN, is a medication used mostly for cystic acne. It was first developed for brain, pancreatic and other cancers. It is used to treat harlequin-type ichthyosis, a usually lethal skin disease, and lamellar ichthyosis. Its effects are systemic and nonselective...

     is introduced in the United States, and later found to be a teratogen, highly likely to cause birth defects if taken during pregnancy. In the United States, more than 2,000 women became pregnant while taking the drug between 1982 and 2003, with most pregnancies ending in abortion
    Abortion
    Abortion is defined as the termination of pregnancy by the removal or expulsion from the uterus of a fetus or embryo prior to viability. An abortion can occur spontaneously, in which case it is usually called a miscarriage, or it can be purposely induced...

     or miscarriage
    Miscarriage
    Miscarriage or spontaneous abortion is the spontaneous end of a pregnancy at a stage where the embryo or fetus is incapable of surviving independently, generally defined in humans at prior to 20 weeks of gestation...

    . About 160 babies with birth defects were born.

Research

A vaccine against inflammatory acne has been tested successfully in mice, but it is not certain that it would work similarly in humans.

A 2007 microbiology
Microbiology
Microbiology is the study of microorganisms, which are defined as any microscopic organism that comprises either a single cell , cell clusters or no cell at all . This includes eukaryotes, such as fungi and protists, and prokaryotes...

 article reporting the first genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....

 sequencing
DNA sequencing
DNA sequencing includes several methods and technologies that are used for determining the order of the nucleotide bases—adenine, guanine, cytosine, and thymine—in a molecule of DNA....

 of a Propionibacterium acnes
Propionibacterium acnes
Propionibacterium acnes is a relatively slow growing, typically aerotolerant anaerobic gram positive bacterium that is linked to the skin condition acne; it can also cause chronic blepharitis and endophthalmitis, the latter particularly following intraocular surgery...

bacteriophage
Bacteriophage
A bacteriophage is any one of a number of viruses that infect bacteria. They do this by injecting genetic material, which they carry enclosed in an outer protein capsid...

 (PA6) said this "should greatly enhance the development of a potential bacteriophage therapy
Phage therapy
Phage therapy is the therapeutic use of bacteriophages to treat pathogenic bacterial infections. Although extensively used and developed mainly in former Soviet Union countries circa 1920, this method of therapy is still being tested for treatment of a variety of bacterial and poly-microbial...

 to treat acne and, therefore, overcome the significant problems associated with long-term antibiotic therapy and bacterial resistance
Antibiotic resistance
Antibiotic resistance is a type of drug resistance where a microorganism is able to survive exposure to an antibiotic. While a spontaneous or induced genetic mutation in bacteria may confer resistance to antimicrobial drugs, genes that confer resistance can be transferred between bacteria in a...

."
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