Acne

Acne is an inflammatory disease of the skin, caused by changes in the pilosebaceous units (skin structures consisting of a hair follicle and its associated sebaceous gland). The most common form of acne is known as "acne vulgaris", which means common acne. Excessive secretion of oils from the glands combine with naturally occurring dead skin cells to block the hair follicles. Oil secretions build up beneath the blocked pore, providing a perfect environment for the skin bacteria Propionibacterium acnes to multiply uncontrolled. In response, the skin inflames, producing the visible lesion.

Available treatments

There are many products sold for the treatment of acne, many of them without any scientifically-proven effects. However, a combination of treatments can greatly reduce the amount and severity of acne in many cases. It is highly advisable to ask a dermatologist about the tradeoffs between these treatments for any individual case, especially when considering using any of them in combination. There are a number of treatments that have been proven effective:

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• Killing the bacteria that are harbored in the blocked follicles. This is done either by the intake of antibiotics like the three 'cyclines (tetracycline, doxycycline and minocycline), or by treating the affected areas externally with bactericidal substances like benzoyl peroxide or erythromycin. However, reducing the P.acnes bacteria will not, in itself, do anything to reduce the oil secretion and abnormal cell behaviour that is the initial cause of the blocked follicles. Additionally the antibiotics are becoming less and less useful as resistant P.Acnes is becoming common. Benzoyl Peroxide has the advantage of being a strong oxidiser and does not appear to generate resistance. Acne will generally reappear quite soon after the end of treatment—days later in the case of topical applications, and weeks later in the case of oral antibiotics.
• Reducing the secretion of oils from the glands. This is done by a daily oral intake of Vitamin A derivates like isotretinoin over a period of a few months. Isotretinoin has been shown to be very effective in treating severe acne and is effective in 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 (which can be severe). About 25% of patients may need a second treatment for another few months to obtain desired results. The most common side effects are dry skin and nosebleed. Reports that it can also permanently damage the liver are unsubstantiated, and routine testing is considered unnecessary by many dermatologists. Some press reports suggest that isotretinoin may cause depression but as of Sept 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 as a last resort after milder treatments have proven insufficient. Very restrictive rules for use will be in force in the USA beginning in 2006. https://www.ipledgeprogram.com/Documents/Prescribers%20Guide%20v3_0A.pdf This has occasioned widespread editorial comment. http://www.usnews.com/usnews/opinion/articles/050905/5healy.htm
• Normalizing the follicle cell lifecycle. A group of medications for this are topical retinoids such as tretinoin (brand name Retin-A), adapalene (brand name Differin) and tazarotene (brand name Tazorac). Like isotretinoin, they are related to Vitamin A, but they are administered as topicals and generally have much milder side effects. They can, however, cause significant irritation of the skin. The retinoids appear to influence the cell creation and death lifecycle 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 over 30 years but are available only on prescription so are not as widely used as the other topical treatments.
• Exfoliating the skin. This can be done either mechanically, using an abrasive cloth or a liquid scrub, or chemically. Common chemical exfoliating agents include salicylic acid and glycolic acid, which encourage the peeling of the top layer of skin to prevent a build-up of dead skin cells which combine with skin oil to block pores. It also helps to unblock already clogged pores. Note that the word "peeling" is not meant in the visible sense of shedding, but rather as the destruction of the top layer of skin cells at the microscopic level. Depending on the type of exfoliation used, some visible flaking is possible. Moisturizers and anti-acne topicals containing chemical exfoliating agents are commonly available over-the-counter.
• Hormonal treatments. In females, acne can be improved with a combined oestrogen/progestogen contraceptive pill. Cyproterone (Diane 35) is particularly effective at reducing androgenic hormone levels and until recently was the best oral contaceptive treatment. It 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.
• Phototherapy. It has long been known that short term improvement can be achieved with sunlight. However studies have shown that sunlight worsens acne long-term, presumably due to UV damage. More recently, visible light has been successfully employed to treat acne - in particular intense blue light generated by purpose-built fluorescent lighting, LEDs or lasers. Used twice weekly, this has been shown to reduce the number of acne lesions by about 64% http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12413768&dopt=Abstract; and is even more effective when applied daily. The mechanism appears to be that porphyrins produced by P. acnes generate free radicals when irradiated by blue light. Particularly when applied over several days, these ultimately kill the bacteria http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=12589953. Extensive basic science and clinical work first initiated by dermatologists Yoram Harth and Alan Shalita have shown that intense blue/violet light (405-425 nanometer) can decrease the number of inflammtory acne lesion by 60-70% in 4 weeks of therapy. Since porphyrins are not otherwise present in skin, and no UV light is employed, it appears to be safe, and has been licensed by the U.S. FDA http://www.fda.gov/fdac/departs/2002/602_upd.html#acne. The treatment apparently works even better if used with red visible light; and overall it has better clearance than benzoyl peroxide. Unlike most of the other treatments few if any negative side effects are typically experienced, and bacterial resistance is unlikely. After treatment, clearance can be longer lived than is typical with topical or oral antibiotic treatments, several months is not uncommon. However, the equipment is relatively expensive, and the treatment works best for mild-moderate acne.

Less widely used treatments include:

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• Azelaic acid (brand names Azelex, Finevin, Skinoren) is suitable for mild, comedonal acne. http://www.nlm.nih.gov/medlineplus/druginfo/uspdi/202783.html
• Zinc. Orally administered zinc gluconate has been shown to be effective in the treatment of inflammatory acne, although less so than tetracyclines. http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=2575335 http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=11586012
• Alternative treatments. Nicholas Perricone's controversial book The Acne Prescription proposes an alternative treatment for adult acne, including a strict diet (dairy is totally avoided in all but two recipes) and topicals containing alpha lipoic acid. Perricone's claims did not seem to be backed up by strong scientific evidence until the publication of the acne / milk link in early 2005. There are no double-blind studies proving the effectiveness of fatty acids against acne.

Popping a pimple or any physical acne treatment should not be attempted by anyone but a qualified dermatologist. Pimple popping irritates skin, can spread the infection deeper into the skin and can cause permanent scarring.

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