Our main sources of evidence included all systematic reviews on acne published since 1999 which have been mapped by NHS Evidence—skin disorders annual evidence updates,1 supplemented by specific searches on Medline for articles published between January, 2003, and Jan 16, 2011, using the search terms “acne”, “comedones”, “vulgaris”, and “aetiology”, “causes”, “natural history”, “pathophysiology”, “treatment”, “management”, and “guidelines”. We also scrutinised citation lists from retrieved
SeminarAcne vulgaris
Introduction
Acne is a disease of the pilosebaceous unit—hair follicles in the skin that are associated with an oil gland (figure 1).2 The clinical features of acne include seborrhoea (excess grease), non-inflammatory lesions (open and closed comedones), inflammatory lesions (papules and pustules), and various degrees of scarring. The distribution of acne corresponds to the highest density of pilosebaceous units (face, neck, upper chest, shoulders, and back). Nodules and cysts comprise severe nodulocystic acne. This Seminar summarises information relating to the clinical aspects of common acne (acne vulgaris). Acne classification, scarring, acne rosacea, chloracne, acne associated with polycystic ovary syndrome, infantile acne, acne inversa, and drug-induced acne have been reviewed elsewhere.3, 4, 5, 6, 7, 8, 9, 10
Section snippets
Prevalence and natural history
Some degree of acne affects almost all people aged 15 to 17 years,11, 12, 13 and is moderate to severe in about 15–20%.8, 12, 14 Prevalence estimates are difficult to compare because definitions of acne and acne severity have differed so much between studies, and because estimates are confounded by the availability and use of acne treatments.15 Surveys of self-reported acne have proven unreliable.16 Although perceived as a teenage disease, acne often persists into adulthood.17, 18 One
Cause
Risk factors and genes associated with acne prognosis and treatment are unclear.31, 32 Twin studies have pointed to the importance of genetic factors for more severe scarring acne.33 A positive family history of acne doubled the risk of significant acne in a study of 1002 Iranian 16-year-olds,14 and the heritability of acne was 78% in first-degree relatives of those with acne in a large study of Chinese undergraduates.34 Acne appears earlier in girls, but more boys are affected during the
Disease mechanisms
Four processes have a pivotal role in the formation of acne lesions: inflammatory mediators released into the skin; alteration of the keratinisation process leading to comedones; increased and altered sebum production under androgen control (or increased androgen receptor sensitivity); and follicular colonisation by P acnes.27 The exact sequence of events and how they and other factors interact remains unclear.
Immune-mediated inflammatory processes might involve CD4+ lymphocytes and macrophages
How does acne affect people?
Acne results in physical symptoms such as soreness, itching, and pain, but its main effects are on quality of life. Psychological morbidity is not a trivial problem,65 and it is compounded by multiple factors: acne affects highly visible skin—a vital organ of social display; popular culture and societal pressures dictate blemishless skin; acne can be dismissed by health-care professionals as a trivial self-limiting condition; and acne peaks in teenage years, a time crucial for building
Skin hygiene
There is no good evidence that acne is caused or cured by washing.46 Antibacterial skin cleansers might benefit mild acne, and acidic cleansing bars are probably better than standard alkaline soaps. However, excessive washing and scrubbing removes oil from the skin surface, drying it and stimulating more oil production. Antibacterial skin cleansers provide no additional benefit to patients already using other, potentially irritating topical treatments.46
Counselling and support
Spending time dispelling myths and
Topical treatments
Topical agents when used alone or in combination effectively treat mild acne consisting of open and closed comedones with a few inflammatory lesions.77 The many treatment options offer different modes of action. Although all are more effective than placebo, establishing the most appropriate strategy for initial and maintenance treatment requires further research.77, 80 Topical treatments only work where applied. Because topical therapies reduce new lesion development they require application to
Oral antibiotics
Oral antibiotics are usually reserved for more severe acne, acne predominantly on the trunk, acne unresponsive to topical therapy, and in patients at greater risk of scarring. Although antibiotics have shown effectiveness in terms of reducing the number of inflammatory lesions, none clear acne completely. Most patients seek acne clearance rather than reduction in lesion counts. There is no conclusive evidence that one antibiotic is more effective than another (including first and second
Complementary and alternative medications (CAMs)
The use of CAMs for acne is widespread. A systematic review of CAM treatments for acne in 2006 identified 15 RCTs covering diverse approaches such as Aloe vera, pyridoxine, fruit-derived acids, kampo (Japanese herbal medicine), and ayurvedic herbal treatments.108 Although mechanisms of potential benefit for some of the CAM therapies were biologically plausible, the included studies were generally of poor quality and inconclusive. Another systematic review found some benefit for acupuncture with
Special clinical problems
The depth and extent of acne scarring varies and can be improved by multiple procedures including subcision, punch excision, laser resurfacing, dermabrasion, and chemical peels.27, 112 Increasingly acne scarring is being treated with fractionated laser treatments—a technique that produces thousands of microthermal areas of dermal ablation separated by areas of untreated skin, with fewer side-effects and a quicker healing period than ablative lasers.113
Whereas open comedones can often be
Retinoid safety
Topical retinoids, a first-line acne therapy in the USA, have been associated with increased deaths in older male veteran patients in a randomised controlled trial of actinic keratosis.125 Although this finding has been ascribed to chance, informing all topical retinoid users of these results might be warranted until further data are obtained.126 A branded form of oral isotretinoin (Accutane) was introduced in the USA in 1982 and has been used by more than 13 million patients, but has now lost
Search strategy and selection criteria
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