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. This ongoing battle and long-lasting cycle is both wearisome and frustrating.

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 mild to moderate acne due to hormonal changes associated with pregnancy, their menstrual cycles, or starting or stopping birth control pills.

Teenage and adult acne can take months or years to treat successfully. 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. Acne treatment for mild cases usually involves self-care measures, such as washing your skin daily with a gentle cleanser and using an over-the-counter acne cream. Acne treatment for severe cases usually includes one or more prescription medications. Once acne is under control, prevention strategies can help keep your skin clear of breakouts.

Acne typically appears on your face, neck, chest, back and shoulders, which are the areas of your skin with the largest number of functional oil glands.

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, foods have little effect on acne. Acne also 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.