What Is Acne?

Acne is a disorder resulting from the action of hormones on the skin's oil glands (sebaceous glands), which leads to plugged pores and outbreaks of lesions commonly called pimples or zits. Acne lesions usually occur on the face, neck, back, chest, and shoulders. Nearly 17 million people in the United States have acne, making it the most common skin disease. Although acne is not a serious health threat, severe acne can lead to disfiguring, permanent scarring, which can be upsetting to people who are affected by the disorder.

How Does Acne Develop?

Doctors describe acne as a disease of the pilosebaceous units (PSUs). Found over most of the body, PSUs consist of a sebaceous gland connected to a canal, called a follicle, that contains a fine hair (see "Normal Pilosebaceous Unit" diagram, below). These units are most numerous on the face, upper back, and chest. The sebaceous glands make an oily substance called sebum that normally empties onto the skin surface through the opening of the follicle, commonly called a pore. Cells called keratinocytes line the follicle.

Normal Pilosebaceous Unit

The hair, sebum, and keratinocytes that fill the narrow are finding that, over time, the bacteria that are associated with acne are becoming resistant to treatment with certain antibiotics. Research is also being conducted by industry on the potential side effects of isotretinoin and the long-term use of medicines used for treating acne.

Scientists are working on other means of treating acne. For example, researchers are studying the biology of sebaceous cells and testing a laser in laboratory animals to treat acne by disrupting sebaceous glands. Scientists are also studying the treatment of androgenic disorders, including acne, in men by inhibiting an enzyme that changes testosterone to a more potent androgen.