Health A-Z

Medical Content Created by the Faculty of the
Harvard Medical School

Acne

What Is It?

Acne is a common skin condition 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, which moisturizes hair and skin. Each hair penetrates up through the skin surface along with sebum.

Acne may begin during puberty, and it affects about 80 percent of all adolescents. It occurs when sebaceous glands in the skin are over-stimulated to produce sebum. Skin cells are not being shed normally, and these sticky cells block the skin's hair follicles, trapping the sebum. The blocked, oil-filled follicle then causes the bacteria normally in the hair follicles to multiply. This leads to inflammation, redness and pimples (pustules).

In adolescents, acne flare-ups probably are related to a natural increase in androgen hormones during the teen years that stimulate the sebaceous glands to produce excess sebum. Hereditary factors also contribute to the problem. Other factors that can lead to acne include the use of oily cosmetics, humidity, heavy sweating, and problems with the ovaries or adrenal glands. Acne also can be triggered by drugs such as lithium or steroids, both the type that are prescribed by physicians and potentially harmful "body-building" steroids. Acne is not related to diet or poor hygiene. In fact, too much washing can cause an acne flare-up to get worse.

Acne is a common skin condition 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, which moisturizes hair and skin. Each hair penetrates up through the skin surface along with sebum.

Acne may begin during puberty, and it affects about 80 percent of all adolescents. It occurs when sebaceous glands in the skin are over-stimulated to produce sebum. Skin cells are not being shed normally, and these sticky cells block the skin's hair follicles, trapping the sebum. The blocked, oil-filled follicle then causes the bacteria normally in the hair follicles to multiply. This leads to inflammation, redness and pimples (pustules).

In adolescents, acne flare-ups probably are related to a natural increase in androgen hormones during the teen years that stimulate the sebaceous glands to produce excess sebum. Hereditary factors also contribute to the problem. Other factors that can lead to acne include the use of oily cosmetics, humidity, heavy sweating, and problems with the ovaries or adrenal glands. Acne also can be triggered by drugs such as lithium or steroids, both the type that are prescribed by physicians and potentially harmful "body-building" steroids. Acne is not related to diet or poor hygiene. In fact, too much washing can cause an acne flare-up to get worse.