The prevalence of patients over the age of 25 years with acne has significantly increased over the past 10 years. Several etiologic factors such as genetic factor, hyperandrogenism, stress, and cosmetics have been studied.

The purpose of this study is to evaluate the differences between adolescent acne and post-adolescent acne, based on the clinical features, asoociated diseased and aggravating factors of 327 acne patients.

327 consective patients, first visited to our hospital with clinical facial acne between March 2000 and February 2001, were enrolled. 220 adolescent patients(AP) were under the age of 25 and post-adolescent patients(PP) were over age of 25.

1. In the face, cheeks and forehead in adolescents, chin and cheeks in post-adolescents were predilection sites. The predominant type was a comedonal type in adolescents and a papulopustular type in post-adolescents(P<0.05). Severity of inflammatory type was not different between two groups. Familial factors were important in both groups, but more frequently found in post-adolescents with persistent acne(P<0.05).

2. Rosacea, chloasma, and hyperandrogenic features such as hirsutism and androgenetic alopecia were more frequently observed in post-adolescents. Seborrheic and atopic dermatitis were more frequent in adolescents. Four patients had all the features of chloasma, acne, rosacea, seborrheic dermatitis and hirsutism.

3. Aggravation by weason especially summer, sweating, stress, and cosmetics was more frequent in adolescents. In PP, acne was more frequently aggravated by sunlight, foods and menstrual period.

Post-adolescent acne was mainly a papulopustular type predominantly located on the chin and cheeks with mild to moderated severity, and family history and hyperandrogenism were strong etiologic factors in persistent acne. Aggravating factors were not significantly different between two group, which suggested cosmetics and stress might not be important in post adolescent acne.