Overview of Seborrheic Dermatitis
Seborrheic dermatitis is a common, chronic condition that occurs in areas of the skin where there are large oil glands—the middle of the face, behind the ears, and especially on the scalp (dandruff). The condition is characterized by waxy scale and reddened skin areas. It affects approximately 3 to 5 percent of the population, most commonly men, and peaks in infancy and middle age.
Causes of Seborrheic Dermatitis
Despite many attempts, researchers have been unable to identify a precise cause of seborrheic dermatitis. The most popular theory is that it is caused by a sensitivity to yeast on the skin, although research data is inconclusive; however, people with the condition often respond to antifungal medications. Certain drugs (e.g., methyldopa, cimetidine [Tagamet], antiseizure medications) can aggravate seborrheic dermatitis.
Up to 85 percent of people infected with the human immunodeficiency virus (HIV) have seborrheic dermatitis, and as their immunity wanes, the eruptions become more severe.