Acne affects between 50-80% of teenagers and young adults. It is a disorder of the pilosebaceous unit (hair follicle and associated oil gland). Factors that contribute to acne formation include increased sebum (a substance made up of oil and wax that functions to protect the skin), increased build-up of material in the hair follicle, increased levels of Propionibacterium acnes (a bacteria that is commonly present on the skin in low numbers), and inflammation...