Seborrheic dermatitis is chronic inflammation that causes yellow, greasy scales and dandruff to form on areas of the skin that have a high number of oil glands such as the scalp and face, along the hairline, around the ears, and occasionally on other areas.
(See also Overview of Dermatitis.)
The cause of seborrheic dermatitis is unknown, but the number of Malassezia yeasts, an organism normally present on the skin, and a person's reaction to them play some role.
Seborrheic dermatitis occurs most often in infants, usually within the first 3 months of life, and in adults 30 to 70 years old.
The risk and severity of the disorder seems to be affected by genetic factors, often runs in families, and is worse in cold weather. Seborrheic dermatitis may be more common and more severe among people who have a neurologic disorder (especially Parkinson disease) and among people who have HIV/AIDS.
Symptoms of Seborrheic Dermatitis
Seborrheic dermatitis usually begins gradually, causing dry or greasy scaling of the scalp (dandruff), sometimes with itching but without hair loss.
In severe cases, yellowish to reddish scaly raised bumps appear along the hairline, behind the ears, on the eyebrows, in the folds of skin on the sides of the nose, and on the chest.
In infants younger than 1 month of age, seborrheic dermatitis may produce a thick, yellow, crusted scalp rash (cradle cap) and sometimes yellow scaling behind the ears and red pimples on the face. Frequently, a stubborn diaper rash accompanies the scalp rash.
Older children and adults may develop a thick, tenacious, scaly scalp rash with large flakes of skin.
Diagnosis of Seborrheic Dermatitis
The location and appearance of the affected skin
Doctors base the diagnosis of seborrheic dermatitis on the location and appearance of the affected skin.
Treatment of Seborrheic Dermatitis
Shampoos, antifungal creams, corticosteroid creams and solutions, and sometimes calcineurin inhibitors
Adults and older children
Malassezia
If the shampoos do not relieve itching, people can apply a corticosteroid solution to the scalp. Seborrheic dermatitis in beard and eyebrow areas is treated similarly to seborrheic dermatitis of the scalp.
Often, treatment must be continued for many weeks. If seborrheic dermatitis returns after the treatment is stopped, treatment can be restarted.
