What Causes Acne?

The exact cause of acne is unknown, but doctors believe it results from several related factors. One important factor is an increase in hormones called androgens (male sex hormones). These increase in both boys and girls during puberty and cause the sebaceous glands to enlarge and make more sebum. Hormonal changes related to pregnancy or starting or stopping birth control pills can also cause acne.

Another factor is heredity or genetics. Researchers believe that the tendency to develop acne can be inherited from parents. For example, studies have shown that many school-age boys with acne have a family history of the disorder. Certain drugs, including androgens and lithium, are known to cause acne. Greasy cosmetics may alter the cells of the follicles and make them stick together, producing a plug.

Factors That Can Make Acne Worse

Factors that can cause an acne flare include:

• Changing hormone levels in adolescent girls and adult women 2 to 7 days before their menstrual period starts

• Oil from skin products (moisturizers or cosmetics) or grease encountered in the work environment (for example, a kitchen with fry vats)

• Pressure from sports helmets or equipment, backpacks, tight collars, or tight sports uniforms

• Environmental irritants, such as pollution and high humidity

• Squeezing or picking at blemishes

• Hard scrubbing of the skin

• Stress.

Myths About the Causes of Acne

There are many myths about what causes acne. Chocolate and greasy foods are often blamed, but there is little evidence that foods have much effect on the development and course of acne in most people. Another common myth is that dirty skin causes acne; however, blackheads and other acne lesions are not caused by dirt. Stress doesn't cause acne, but research suggests that for people who have acne, stress can make it worse.

Part 1: What is acne?

Part 2: What is acne? ...continued

Part 3: What causes acne?

Part 4: How is acne treated?

Part 5: How should I care for my skin?

Part 6: Current research for acne?

Source: Adapted from National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)