Acne vulgaris the most common dermatologic disorder treated by physicians, affecting 80% of persons aged 11 to 30 years old. Because acne usually presents in early adolescence, pediatricians must be familiar with current recommendations about acne management. Appropriate management depends on a number of factors, including the types and numbers of lesions present, the patient’s experiences with medications, and personal preferences. Growing knowledge about the multifactorial etiology of acne has led to new recommendations in favor of combination therapy and against monotherapy with antibiotics.

The microcomedo is now known to be the precursor of all acne lesions, inflammatory and noninflammatory. It develops from the pilosebaceous unit, which consists of the hair follicle, the hair shaft, and the sebaceous gland. The four primary factors contributing to the development of acne lesions are abnormal desquamation of keratinocytes within the pilosebaceous unit, increased sebum production, proliferation of Propionibacterium acnes (a gram-positive anaerobe that resides in the pilosebaceous unit), and inflammation.

The two main types of acne lesions are comedonal and inflammatory, and their etiology depends on the relative contribution of the preceding factors. Noninflammatory acne lesions are comedones. They may be open (i.e., blackheads) or closed (i.e., whiteheads). Closed comedones are small white papules with no surrounding erythema, containing only a microscopic opening to the skin surface. P. acnes is associated with inflammatory lesions (i.e., pimples). Inflammatory lesions are characterized by erythema. They may be papules and pustules (<5 mm in diameter) or nodules, which measure >5 mm and involve more than one follicle. The severity of inflammatory/pustular acne depends on the level of antibody, complement, and cell-mediated immune responses to the bacterium, rather than an infectious etiology. Large deep lesions that coalesce may form cysts. Scars may develop as inflammatory lesions resolve. Facial scars may appear as small pits,
whereas truncal scars tend to be small hypopigmented spots. Scars may be irreversible and their presence may lead clinicians to be more aggressive in selecting anti-inflammatory therapeutic agents.