Pathogenesis of acne vulgaris: recent advances.

Acne vulgaris is the most common disorder seen in ambulatory dermatology practice. Acne causes significant morbidity and the direct costs associated with it exceed $2.2 billion per year in the United States (U.S.). The pathogenesis is multifactorial, and our understanding of the mechanisms involved in the development of acne lesions has improved with time. Follicular hyperkeratinization, sebum production, presence of Propionibacterium acnes (P. acnes), inflammatory mediators, and androgens have been identified as key components of acne pathophysiology. Recent advances have been made in this area with the discovery of P. acnes interaction with Toll-like receptors (TLRs), vaccines targeting P. acnes or its components, antimicrobial peptides and the role of hormones.