Acne is a common disorder in adolescents and young adults. Itresults from alterations taking place in pilosebaceous follicles. Thesestructures are most abundant on the face, chest and upper back.Several sequential biological steps are involved in the initiation,maturation and regression of each acne lesion. At first, during thepreadolescent age, hormonal changes progressively lead toincreased circulating androgens, both in boys and girls. Androgenreceptors are present in the sebaceous gland apparatus. Theirstimulation leads to increasing the size of the sebaceous gland, thesebum flow (skin greasiness) and the size of opening of theexcretion duct at the skin surface (skin pore, acroinfundibulum).Second, the maturation of the epithelial wall of scatteredacroinfundibula is altered leading to the accumulation of tightlyadherent corneocytes. ...