Most common skin ailment in 2nd and 3rd decades. Boys tend to have a peak incidence between 16 and 19 years girls have a peak incidence 14 and 16 years. Acne is a multifactorial disease, the lesion of acne vulgaris occur in the sebaceous follicle, increase sensitivity of sebaceous glands to normal amounts of circulating androgens. Bacterial colonization of sebaceous follicles is another important factor. Pityrosporum oval, staph, epidermidis and propionibacterium acnes are found in the follicle. Microcomedones—blackhead, whitehead. Characteristic pathognomonic lesion is an open or a closed comedone. Course waxes and wanes. Treatment: Local: Sulphur, resorcinol and salicylic acid have given newer topical agent like-benzoyl peroxide, retinoic acid. Topical antibiotics: One to two percent clindamycin. Physical modalities for scar in acne. Cryotherapy can produce peeling. Retinoids: 13-cis- retinoic acid reduce production of sebum. Varieties of acne: Acne in infants, acne excoriee, and acne conglobate acne fulminans. Drugs causing acneiform eruptions important once are INH, iodides, lithium, corticosteroids. Occupational acne-many oils and tars produce acneiform lesions at the site of contact.