Seborrheic dermatitis

[Zipporah Schumaker]

Seborrheic dermatitis is chronic inflammation that causes yellow, greasy scales and dandruff to form on the scalp and face, along the hairline, around the ears, and occasionally on other areas.
(See also Overview of Dermatitis.)
The cause is unknown, but the number of Malassezia yeasts, an organism normally present on the skin, plays some role. Seborrheic dermatitis occurs most often in infants, usually within the first 3 months of life, teens, and in those aged 30 to 70 years. The disorder is more common among men, often runs in families, and is worse in cold weather. Emotional or physical stress seems to worsen seborrheic dermatitis. A form of seborrheic dermatitis also occurs in as many as 85% of people with AIDS. Seborrheic dermatitis is also common among people with Parkinson disease.