Acne. Zits. Pimples. Blemishes. No matter what you call them, acne can be distressing and annoyingly persistent. Acne lesions heal slowly, and when one begins to resolve, others seem to crop up.

Hormones likely play a role in the development of acne, making the condition most common in teenagers. But people of all ages can get acne. Some adult women experience acne due to hormonal changes associated with pregnancy, their menstrual cycles, or starting or stopping birth control pills.

Depending on its severity, acne can cause emotional distress and lead to scarring of the skin. The good news is that effective treatments are available — and the earlier treatment is started, the lower your risk of lasting physical and emotional damage.

Three factors contribute to the formation of acne:

• Overproduction of oil (sebum)
• Irregular shedding of dead skin cells resulting in irritation of the hair follicles of your skin
• Buildup of bacteria

Acne occurs when the hair follicles become plugged with oil and dead skin cells. Each follicle is connected to sebaceous glands. These glands secrete an oily substance known as sebum to lubricate your hair and skin. Sebum normally travels up along the hair shafts and then out through the opening of the hair follicle onto the surface of your skin. When your body produces an excess amount of sebum and dead skin cells, the two can build up in the hair follicle and form together as a soft plug.

This plug may cause the follicle wall to bulge and produce a whitehead. Or, the plug may be open to the surface and may darken, causing a blackhead. Pimples are raised red spots with a white center that develop when blocked hair follicles become inflamed or infected. Blockages and inflammation that develop deep inside hair follicles produce lumps beneath the surface of your skin called cysts. Other pores in your skin, which are the openings of the sweat glands onto your skin, aren't normally involved in acne.

It's not known what causes the increased production of sebum that leads to acne. But a number of factors — including hormones, bacteria, certain medications and heredity — play a role.

Contrary to what some people think, greasy foods and chocolate have little effect on acne. Studies are ongoing to determine whether other dietary factors — including high-starch foods, such as bread, bagels and chips, which increase blood sugar — may play a role in acne.

Acne isn't caused by dirt. In fact, scrubbing the skin too hard or cleansing with harsh soaps or chemicals irritates the skin and can make acne worse. Simple cleansing of the skin to remove excess oil and dead skin cells is all that's required.

Hormonal changes in your body can provoke or aggravate acne. Such changes are common in:

• Teenagers, both in boys and girls
• Women and girls, two to seven days before their periods
• Pregnant women
• People using certain medications, including cortisone

Other risk factors include:

    * Direct skin exposure to greasy or oily substances, or to certain cosmetics applied directly to the skin
    * A family history of acne — if your parents had acne, you're likely to develop it too
    * Friction or pressure on your skin caused by various items, such as telephones or cell phones, helmets, tight collars and backpacks