Acne is most common during adolescence, affecting more than 85% of teenagers, and frequently continues into adulthood. For most people, acne diminishes over time and tends to disappear, or at least decrease, after one reaches his or her early twenties. There is, however, no way to predict how long it will take for it to disappear entirely, and some individuals will continue to suffer from acne decades later, into their thirties and forties and even beyond.
The face and upper neck are the most common areas affected, but the chest, back and shoulders may have acne as well. The typical acne lesions are comedones and 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.
Aside from scarring, its main effects are psychological. This includes lowered self-esteem, which maybe a contributing factor leading to adolescent depression or suicide. Acne usually appears during adolescence, when people already tend to be most socially insecure. Early and aggressive treatment is therefore advocated by some to lessen the overall impact to individuals.
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 comedo (blackhead) or closed comedo (whitehead). In these conditions the naturally
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