Acne occurs most commonly during adolescence, affecting an estimated 80-90% of teenagers in the Western world. People may also be affected before and after puberty. Though it becomes less common in adulthood than in adolescence, nearly half of people in their twenties and thirties continue to have acne. About 4% continue to have difficulties into their forties.
It has been estimated that up to 30% of teenagers have acne of sufficient severity to require medical treatment. Overall incidence of acne is similar in both men and women, and peaks at 17 years of age. The number of adults with acne, including people over 25 years, is increasing; the reasons for which are unclear.