Acne is a disorder caused by clogged hair follicles and sebaceous glands, which can lead to pimples and cysts.

Acne is very common; nearly 80 percent of Americans between ages 11 and 30 years old will be affected by it at some point.


Acne most often begins in puberty, when the male sex hormones (androgens) increase in both boys and girls. This causes the sebaceous glands to become more active, which results in increased production of oil, or sebum.

Sebum normally travels from the sebaceous glands to the skin surface via hair follicles. However, skin cells can plug the follicles, blocking the sebum. When follicles become plugged, skin bacteria begin to grow inside the follicles, causing inflammation.

Black Heads: Incomplete blockage of the hair follicle results in blackheads.

White Heads: Complete blockage of the hair follicle results in whiteheads.

Pimples: Eventually, the plugged follicle bursts, spilling oil, skin cells, and bacteria onto the skin surface. In turn, the skin becomes irritated and pimples or lesions begin to develop. Acne can be superficial (pimples without abscesses) or deep (when the inflamed pimples push down into the skin, causing pus-filled cysts that rupture and result in larger abscesses).

Body Acne: Acne can occur anywhere on the body. However, it most often appears in areas where there’s a high concentration of sebaceous glands, including the face, chest, upper back, shoulders, and neck.

Rising hormone levels during puberty are one cause of acne. In addition, acne is often inherited. Other causes may include hormone-level changes during the menstrual cycle; certain drugs (such as corticosteroids, lithium, and barbiturates); oil and grease from the scalp, mineral or cooking oil, or certain cosmetics; and bacteria inside pimples.

Acne can be aggravated by squeezing the pimples or by scrubbing the skin too hard. Skin may also become irritated with friction or pressure from helmets, backpacks, or tight collars. Some environmental conditions such as pollution or humidity can irritate the skin as well.


The goal of acne treatment is to minimize scarring and improve appearance. Depending on the severity of acne, your doctor may prescribe topical medications (applied to the skin) or systemic medications (taken orally). In some cases, a combination of topical and systemic medications may be recommended.

Although acne often is a chronic condition, even if it ends after adolescence, it can leave life-long scars, which typically look like “ice pick” pit scars or crater-like scars. Although proper treatment for acne may minimize scarring, several dermatological procedures may be helpful as well, including dermabrasion, chemical peels, collagen injections, and laser resurfacing.

Medical Reviewer: [Foster, Sara, RN, MPH, Jenkins, Lee] Last Annual Review Date: 2009-06-05T00:00:00-06:00 Copyright: © 2000-2010 The StayWell Company, 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

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