A chronic skin disorder caused by inflammation of the hair follicles and sebaceous glands in the skin. The most common type is acne vulgaris, which almost always develops during puberty. Acne spots are caused by the obstruction of hair follicles by sebum (the oily substance secreted by the sebaceous glands). Bacteria multiply in the follicle, causing inflammation. The change in sebum secretion at puberty seems to be linked with increased levels of androgen hormones (male sex hormones). Acne may be brought on or aggravated by drugs such as corticosteroids and androgens. Exposure to certain chemicals and oils in the workplace can also cause a type of acne. Acne develops in areas of skin with a high concentration of sebaceous glands, mainly the face, centre of the chest, upper back, shoulders, and around the neck. Milia (whiteheads), comedones (blackheads), nodules (firm swellings beneath the skin), and cysts (larger, fluid-filled swellings) are the most commonly occurring spots. Some, particularly cysts, leave scars after they heal. There is no instant cure for acne, but washing the affected areas at least twice daily may help to keep it under control. Topical drug treatments, such as benzoyl peroxide or retinoic acid, unblock the pores and promote healing. Ultraviolet light can be beneficial. If topical treatment has failed, oral drug treatment with antibiotics, hormones, or isotretinoin may be given. Acne improves slowly over time, often clearing up by the end of the teenage years.


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