Acne may affect any age group, but it is most common in adolescents.
Lesions consist of noninflammatory comedones (whiteheads and blackheads) and inflammatory papules, pustules, nodules, and cysts.
Severity ranges from mild comedonal acne to severe nodulocystic acne, which can be permanently disfiguring.
Systemic effects may also be present with acne fulminans, a rare variant.
Treatments include topical retinoids, keratolytics, and antibiotics; more severe inflammatory lesions may require oral antibiotics; severe nodulocystic acne may require oral isotretinoin.
Acne vulgaris is a skin disease affecting the pilosebaceous unit. It is characterized by comedones, papules, pustules, nodules, cysts, and/or scarring, primarily on the face and trunk. Clinical manifestations range from mild to severe with systemic symptoms. Acne is most common in adolescents, but may occur at any age. In addition to the physical lesions, acne can have profound psychological and social impact on patients. 
MN declares that he has no competing interests.
Dr Mark Naftanel would like to gratefully acknowledge Dr Yolanda Rosi Helfrich, the previous contributor to this monograph. YRH declares that she has no competing interests.
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