Adult Acne, Part I: Causes by Dr. Coyle S. Connolly At Connolly Dermatology in New Jersey, Dr. Coyle S. Connolly provides dermatologic care for a variety of medical conditions and cosmetic concerns. Here, he presents a brief overview of the causes of adult acne, a condition that has been on the rise in recent years. Studies show that adult acne affects approximately 50 percent of post-adolescent women and 25 percent of men. Acne is caused by a combination of blocked pores, increased sebum production, and certain bacteria. Women are particularly susceptible because of the hormonal changes that occur during pregnancy or menopause. In addition, those who take steroids for certain medical conditions may experience an increase in acne. For many adults, however, topical causes can also contribute to acne. Those with sensitive skin may find breakouts occurring as a result of certain cosmetic products or cleansers. As a result, all cleansers and moisturizers should be fragrance free and all cosmetics should be non-comedogenic. Makeup that is mineral-based, not oil-based, is ideal.