This article is about a skin disease commonly found during adolescence. For other acneform skin diseases, see Acne (disambiguation).
This article is about a skin disease commonly found during adolescence. For other acneform skin diseases, see Acne (disambiguation).
| Acne vulgaris | |
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Acne vulgaris (cystic acne or simply acne) is a common human skin 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.[1] 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 isinflammatory, but acne can also manifest in noninflammatory forms.[2] The lesions are caused by changes in pilosebaceous units, skin structures consisting of a hair follicle and its associated sebaceous gland, changes that require androgen stimulation.
Acne occurs most commonly during adolescence, and often continues into adulthood. In adolescence, acne is usually caused by an increase intestosterone, which people of both genders accrue during puberty.[3] For most people, acne diminishes over time and tends to disappear — or at the very least decrease — by age 25.[4] 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.[5]
Some of the large nodules were previously called "cysts" and the term nodulocystic has been used to describe severe cases of inflammatory acne.[6]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.[7] Cystic acne affects deeper skin tissue than does common acne.[8]
Aside from scarring, its main effects are psychological, such as reduced self-esteem[9] and in very extreme cases, depression or suicide.[10] Acne usually appears during adolescence, 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.[9]
Terminology
ypical features of acne include: seborrhea (scaly red skin), comedones (blackheads and whiteheads), papules (pinheads), pustules (pimples), nodules (large papules) and, possibly scarring.[1] It presents somewhat differently in people with dark skin.
Scars
Acne scars 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.[15]
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 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 scars.
- Rolling scars: Scars that give the skin a wave-like appearance.
- Hypertrophic scars: Thickened, or keloid 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 indefinitely if untreated.
Cause
Acne develops as a result of blockages in follicles. Hyperkeratinization and formation of a plug of keratin and sebum (a microcomedo) is the earliest change. Enlargement of sebaceous glands and an increase in sebum production occur with increased androgen (DHEA-S) production at adrenarche. The microcomedo may enlarge to form an open comedone (blackhead) or closed comedone (milia). Comedones are the direct result of sebaceous glands' becoming clogged with sebum, a naturally occurring oil, and dead skin cells. In these conditions, the naturally occurring largelycommensal bacterium Propionibacterium acnes can cause inflammation, leading to inflammatory lesions (papules, infected pustules, or nodules) in the dermis around the microcomedo or comedone, which results in redness and may result in scarring or hyperpigmentation.[16]
[edit]Hormonal
Hormonal activity, such as menstrual cycles and puberty, 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.[17] Use of anabolic steroids may have a similar effect.[18] Several hormones have been linked to acne: the androgens testosterone, dihydrotestosterone(DHT) and dehydroepiandrosterone sulfate (DHEAS), as well as insulin-like growth factor 1 (IGF-I).
Development of acne vulgaris in later years is uncommon, although this is the age group for rosacea, 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 or the rare Cushing's syndrome. Menopause-associated acne occurs as production of the natural anti-acne ovarian hormone estradiol 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).
[edit]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.[19]
[edit]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."[20] The National Institutes of Health (USA) list stress as a factor that "can cause an acne flare."[21] A study of adolescents in Singapore "observed a statistically significant positive correlation […] between stress levels and severity of acne."[22] It is also not clear whether acne causes stress and thus perpetuates itself to some extent.
[edit]Infectious
Propionibacterium acnes (P. acnes) is the anaerobic bacterium species that is widely concluded to cause acne, though Staphylococcus epidermidis has been universally discovered to play some role since normal pores appear colonized only by P.acnes.[23] 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. [24]In vitro, resistance of P. acnes to commonly used antibiotics has been increasing, as well.[25]
[edit]Diet
A high glycemic load diet is associated with worsening acne.[26][27] There is also an association between the consumption of milk and the rate and severity of acne.[26][28] Other associations such as chocolate and salt are not supported by the evidence.[26] However, products with these ingredients often contain a high glycemic load.
[edit]Diagnosis
There are multiple grading scales for grading the severity of acne vulgaris,[29] 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).
[edit]Differential
[edit]Management
Many different treatments exist for acne including benzoyl peroxide, antibiotics, retinoids, antiseborrheic medications, anti-androgen medications,hormonal treatments, salicylic acid, alpha hydroxy acid, azelaic acid, nicotinamide, and keratolytic soaps.[30] They are believed to work in at least 4 different ways, including: normalising shedding into the pore to prevent blockage, killing Propionibacterium acnes, anti-inflammatory effects, hormonal manipulation.[citation needed]
[edit]Medications
- Benzoyl peroxide
Benzoyl peroxide is a first-line treatment for mild and moderate acne vulgaris due to its effectiveness and mild side-effects (primarily an irritantdermatitis). It works against the "P. acnes" bacterium, and normally causes just dryness of the skin, slight redness, and occasional peeling when side-effects occur.[31] 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.[31] Unlike antibiotics, benzoyl peroxide does not appear to generate bacterial resistance.[31]
- Antiseptics
Sometimes benzoyl peroxide topical medication is combined with a salt of hydroxyquinoline, such as potassium hydroxyquinoline sulphate, which has antibacterial properties. One such topical product is available without prescription in the UK.[32]
- Antibiotics
Antibiotics are reserved for more severe cases.[31] With increasing resistance of P. acnes worldwide, they are becoming less effective.[31] Commonly used antibiotics, either applied topically or taken orally, include erythromycin, clindamycin, and tetracyclines such as minocycline.
- Hormones
In females, acne can be improved with hormonal treatments. The common combined estrogen/progestogen methods of hormonal contraception have some effect, but the antiandrogen cyproteronein 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 is now available with fewer side-effects than Diane 35 / Dianette. Both can be used where blood tests show abnormally high levels of androgens, 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 retinoids such as tretinoin (Retin-A), adapalene (Differin), and tazarotene (Tazorac). Like isotretinoin, they are related tovitamin A, 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 of these cells that can create a blockage. Retinol, 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.
- Oral retinoids
A daily oral intake of vitamin A derivative isotretinoin (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 (many of which can be severe).</ref> 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 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[weasel words]suggest that isotretinoin may cause depression, 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 or vow abstinence 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 program) for use were put into force in the USA beginning in March 2006 to prevent misuse, causing occasioned widespread editorial comment.[33]
- Anti-inflammatories
Nicotinamide, (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.[34] 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.[35]
Ibuprofen in combination with tetracycline[36] are used for some moderate acne cases for their anti-inflammatory effects.
Mandelic acid 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 and lactic acid.[37]
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