Acne is a common skin condition. It is caused by inflammation of the hair follicles and oil-producing (sebaceous) glands of the skin.
Hair follicles are the tiny structures that grow hair in the scalp. Sebaceous glands produce sebum. On areas where acne develops, sebaceous glands surround the hair follicles. The combination of the sebaceous glands and the hair follicles is the "pilosebaceous unit," where acne pimples and cysts develop. Sebum moisturizes hair and skin. Each hair pushes up through the skin surface along with sebum.
Acne often begins during puberty. It occurs when sebaceous glands in the skin are over-stimulated to produce sebum and skin cells are not shed normally. These sticky cells block the skin's hair follicles, trapping the sebum.
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