Acne is a chronic inflammatory skin disease that is the most common skin disorder in the United States. Therapy targets the four factors responsible for lesion formation: increased sebum production, hyperkeratinization, colonization by Propionibacterium acnes, and the resultant inflammatory reaction. Treatment goals include scar prevention, reduction of psychological morbidity, and resolution of lesions. Grading acne based on lesion type and severity can help guide treatment. Topical retinoids are effective in treating inflammatory and noninflammatory lesions by preventing comedones, reducing existing comedones, and targeting inflammation. Benzoyl peroxide is an over-the-counter bactericidal agent that does not lead to bacterial resistance. Topical and oral antibiotics are effective as monotherapy, but are more effective when combined with topical retinoids. The addition of benzoyl peroxide to antibiotic therapy reduces the risk of bacterial resistance. Oral isotretinoin is approved for the treatment of severe recalcitrant acne and can be safely administered using the iPLEDGE program. After treatment goals are reached, maintenance therapy should be initiated. There is insufficient evidence to recommend the use of laser and light therapies. Referral to a dermatologist should be considered if treatment goals are not met.
Acne is a chronic inflammatory disease involving the pilosebaceous unit. It is typified by the eruption of a comedo within the follicle, which is preceded by a microcomedo.1 Four main factors lead to the formation of acne lesions: (1) increased sebum production by sebaceous glands, in which androgens have an important role; (2) hyperkeratinization of the follicle, leading to a microcomedo that eventually enlarges into a comedo; (3) colonization of the follicle by the anaerobe Propionibacterium acnes; and (4) an inflammatory reaction.2 The inflammatory events may begin before hyperkeratinization of the follicle.3 Current therapies target these four factors for acute control of flare-ups and long-term maintenance.
Acne is diagnosed by the identification of lesions. The spectrum of acne lesions ranges from noninflammatory open or closed comedones (blackheads and whiteheads; Figure 1) to inflammatory lesions, which may be papules, pustules, or nodules (Figures 2 through 4). Lesions are most likely to occur on the face, neck, chest, and back, where there is a higher concentration of sebaceous glands. Other conditions can mimic acne, and even include the term acne in their nomenclature, but they lack the presence of comedones. Table 1 outlines the differential diagnosis for acne.4 Grading acne based on the type of lesions and their severity can help in deciding which therapies are warranted (Figure 5); however, there is no consensus on the best grading system.