Update on pathogenesis and treatment of acne.

Acne vulgaris is a common cutaneous disorder of the pilosebaceous follicle. More than 45 million people are affected with acne vulgaris. In addition, 80% of people in the United States report that they suffered from acne at one point in life. It is estimated that US consumers spend $1.2 billion each year for the treatment of acne. Typically, lesions are pleomorphic and range from open and closed comedones to inflammatory papules, pustules, cysts, and nodules, and scarring may result. The disease is important, with a significant effect on patients' self-esteem. The pathogenesis is only partially understood and is multifactorial. Successful management of acne requires an understanding of the pathophysiology of disease. The first half of this review discusses new discoveries in the pathogenesis of acne, and the second half introduces new and time-honored therapies.