What is seborrheic dermatitis?

Seborrheic dermatitis is a disease that causes flaking of the skin (say: seb-oh-ree-ick). It usually affects the scalp. In teenagers and adults, it is commonly called “dandruff.” In babies, it is called “cradle cap.”

Seborrheic dermatitis can affect the skin on other parts of the body, such as the face and chest, and the creases of the arms, legs, and groin. Seborrheic dermatitis usually causes the skin to look a little greasy, and scaly or flaky.

Who gets seborrheic dermatitis?

Seborrheic dermatitis most often occurs in babies younger than three months and in adults from 30 to 60 years of age. In adults, it is more common in men than in women.

What causes seborrheic dermatitis?

The exact cause is not known. It may be different in babies and adults. Seborrheic dermatitis may be related to hormones, because the problem often starts in infancy and goes away before puberty. Or the cause might be a fungus, called Pityrosporum ovale. This organism is normally present on the skin in small numbers, but sometimes its numbers increase, resulting in skin problems.

How is seborrheic dermatitis treated?

The treatment of seborrheic dermatitis depends on its location on the body. Treatment also depends on the person's age.

• Seborrheic dermatitis of the scalp (dandruff) in adults and teenagers. Dandruff is usually treated with a shampoo that contains salicylic acid (one brand name: Scalpicin), the prescription medicine selenium sulfide (one brand name: Selsun), ketoconazole (brand name: Nizoral), or pyrithione zinc (one brand name: Head & Shoulders). These shampoos can be used two times a week. Shampoos with coal tar (one brand name: Neutrogena T/Gel) may be used three times a week. If you have dandruff, you might start by using one of these shampoos every day until your dandruff is controlled, and then keep using it at least two times a week.

When you use a dandruff shampoo, rub the shampoo into your wet hair thoroughly and let it stay on your hair and scalp for at least five minutes before rinsing. This gives it time to work.

If the shampoo alone does not help, your doctor might want you to use a prescription steroid lotion once or twice a day, in addition to the shampoo.

• Seborrheic dermatitis of the skin creases in teenagers and adults. Teenagers and adults may use steroid lotions prescribed by a doctor.

• Seborrheic dermatitis of the scalp (cradle cap) in babies. Seborrheic dermatitis of the scalp in babies is treated with medicines that are not as strong as those used in adults. You might start with a mild, nonmedicated baby shampoo. Brushing your baby's scalp with a soft brush, like a toothbrush, can help loosen scales or flakes. But be gentle when massaging or brushing your baby's scalp—a break in the skin might lead to an infection. If a nonmedicated shampoo does not work for your baby, talk to your doctor about using a shampoo that contains tar. Or your doctor may want you to use a prescription shampoo that contains 2 percent ketoconazole.

• Seborrheic dermatitis of the skin creases in babies. Your doctor may want you to use gentle steroid lotions or creams to treat seborrheic dermatitis in the skin creases of your baby.