What Causes Acne?

Contrary to popular belief, chocolate does not cause acne. Still, this myth persists almost 50 years after it was debunked. Back when TV was a novelty, Albert Kligman, M.D., a professor of dermatology at the University of Pennsylvania, gave some teens real chocolate bars, and others chocolate-tasting candy bars that contained no chocolate. None of the teens knew whether they’d eaten the real or fake chocolate. Dr. Kligman then photographed their faces and counted the pimples that developed. There was no difference.

“The chocolate myth has been very persistent,” says Alan Brauer, M.D., founder of TotalCare Medical Center in Palo Alto, California, one of the nation’s first clinics to combine mainstream and complementary therapies. “After all these years, you still hear it.” Most dermatologists also believe that nuts and greasy foods do not trigger pimples.

Another myth is that acne is caused by oily skin or hair. But oil that reaches your skin’s surface isn’t the problem. It’s the oil trapped below the surface that causes your pimples.

What Causes Acne?

• Hormones. Teen acne may result from a surge of androgens, but other hormonal ups and downs can also trigger it, especially in women: the menstrual cycle, giving birth, and taking birth control pills or postmenopausal hormone replacement therapy (HRT). The progestins used in HRT and some birth control pills act like androgens. Recently one type of oral contraceptive was approved as a hormone-regulating acne treatment.
• Stress. Stress stimulates the adrenal glands, poosibly increasing androgen production. “Stress plays a major role in exacerbating acne,” says Diane Berson, M.D., an assistant clinical professor of dermatology at New York University Medical Center. “Women are under more stress today than they were a generation ago. In addition to homemaking responsibilities, they also have careers. It’s a lot to balance.”
• Facial irritation. Do you cradle the telephone handset between your shoulder and chin? Or wear a telephone headset, or athletic gear that hugs your face? The minor irritation these devices cause can aggravate acne. Resting your chin in your hand can do the same.
• Drugs. Some drugs cause acne, among them: lithium, corticosteroids, and hormonal medications. If your face breaks out shortly after starting or changing a medication, the drug may well be the cause. Don’t stop taking your medication. Consult your physician. It’s possible a substitute drug might cause fewer problems.
• Occupations. If you work around grease—as a short-order cook, French fry maker, service station mechanic, etc.—you’re at increased risk of acne because exposure to all that oil can block your pores. “Chloracne,” a particular form of acne, is prevalent among people who work with the chlorinated hydrocarbons found in many pesticides, paints, varnishes, motor oil, and roofing materials.
• Sunlight. Though not common, sun exposure can aggravate acne in some people. Scientists are not sure why.
• Cosmetics. Until recently, cosmetics were an acne bad-guy. The theory was that oily make-up clogged and irritated pores, contributing to pimple formation. But in recent years, to less irritating, water-based, ingredients that are less likely to cause problems.