Acne vulgaris is a common, chronic and recurring disease that involves multiple etiological factors including follicular hyperkeratinization, increased sebum production, Propionibacterium acnes proliferation and inflammation. It affects about 80% of teenagers and young adults and is most prevalent in those aged 12 to 24 years, although it can occur at all ages. As many as 17 million people are thought to be affected in the United States alone and the acne therapeutics market is forecast to show moderate growth in revenues through 2016; market data suggests the global acne market was worth US $2.8 billion in 2009 and is estimated to reach revenues of $3.02 billion by 2016. This moderate increase in revenue is attributed to an overcrowding of the market with generics and increased consumer acceptance of alternative therapies, although the acne therapeutics market is witnessing a shift toward combination products using two or more effective acne treatments.
One of the major causes of acne is the increase in sex hormones, especially androgens such as testosterone, which occurs during puberty. Testerone is converted in the skin to dihydrotestosterone (DHT) by α-reductase, which stimulates the sebaceous glands to enlarge and produce more sebum. The more sebum produced, the worse the acne will become. Further, a study by Lee et al. suggests that DHT may also be involved in the production of proinflammatory cytokines in acne.