Acne lesions are commonly referred to as pimples, blemishes, spots, zits, or simply acne. Acne lesions are caused by changes in pilosebaceous units, skin structures consisting of a hair follicle and its associated sebaceous gland, changes which require androgen stimulation.
Acne occurs most commonly during adolescence, affecting more than 96% of teenagers, and often continues into adulthood. In adolescence, acne is usually caused by an increase in male sex hormones, which people of both genders accrue during puberty. 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 well 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.The "cysts," or boils that accompany cystic acne, can appear on the buttocks, groin, and armpit area, and anywhere else where sweat collects in hair follicles and perspiration ducts. Cystic acne affects deeper skin tissue than does common acne.
Aside from scarring, its main effects are psychological, such as reduced self-esteem and, according to at least one study, 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 sebummicrocomedo) 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 (milia). Comedones are the direct result of sebaceous glands becoming clogged with sebum, a naturally occurring oil, and dead skin cells. In these conditions the naturally occurring largely commensalPropionibacterium 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.[12] (a bacteria
[edit] Primary causes
A 16 year-old with acne on his cheek. Acne is known to be partly hereditary, but no particular genetic cause has been identified. Acne is not contagious or infectious. Several factors are known to be linked to acne:
Hormonal activity,Inflammation, skin irritation or scratching of any sort will activate inflammation.Stress.Hyperactive sebaceous glands, secondary to the three hormone sources above.Bacteria in the pores. Propionibacterium acnes (P. acnes) Use of anabolic steroids.Exposure to certain chemical compounds. Chloracne is particularly linked to toxic exposure to dioxins, namely Chlorinated dioxins
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