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Abstract
Acne vulgaris is a common skin condition, caused by changes in pilosebaceous units, via androgen stimulation. It is characterized by noninflammatory follicular papules or comedones and by inflammatory papules, pustules, and nodules in its more severe forms Acne vulgaris affects the areas of skin with the densest population of sebaceous follicles Acne occurs most commonly during adolescence, affecting more than 89% of teenagers, and frequently continues into adulthood In adolescence, acne is usually caused by an increase in male sex hormones. For most people, acne diminishes over time and tends to disappear—or at the very least decrease—after one reaches one’s early twenties. There is, however, no way to predict how long it will take to disappear entirely, and some individuals will carry this condition into their thirties, forties and beyond The face and upper neck are the most commonly affected, but the chest, back and shoulders may have acne as well. The upper arms can also have acne, but lesions found there are often keratosis pilaris not acne. Typical acne lesions are comedones, inflammatory papules pustules and nodules. Some of the large nodules were previously called ”cysts” and the term nodulocystic has been used to describe severe cases of inflammatory acne Acne develops as a result of blockages in follicles Hyperkeratinization and formation of a plug of keratin and sebum (a microcomedo) is the earliest change. Enlargement of sebaceous glands and an increase in sebum production occur with increased androgen (DHEA-S) production at adrenarche. The microcomedo may enlarge to form an open comedone (blackhead) or closed comedone whitehead). Whiteheads are the direct result of skin pores becoming clogged with sebum, a naturally occurring oil, and dead skin cells. In these conditions the naturally occurring largely commensal bacteria Propionibacterium acnes can cause inflammation, leading to inflammatory lesions (papules, infected pustules, or nodules) in the dermis around the microcomedo or comedone, which results in redness and may result in scarring or hyperpigmentation.