Seborrheic dermatitis is a chronic functional disease of the sebaceous glands marked by an increase in the amount and often alteration in the quality of the sebaceous secretion. When the disease occurs in infancy, it is called cradle cap and usually clears without treatment by age 8 to 12 months. Seborrheic dermatitis also is common in the diaper area, where it can be confused with other forms of dermatitis.
Seborrheic dermatitis is an idiopathic disease. It may occur when individuals have a disease of the nervous system, such as Parkinson disease. Persons with a stressful medical condition such as having had a heart attack also may develop this problem.
Signs and Symptoms
The disease is characterized by skin eruptions on areas of the scalp, eyelids, cheeks, beard, chest, axillae, groin, or trunk that produce dry, moist, or greasy scales. The lesions are brownyellow or red. Such scaling produced by the scalp is commonly called dandruff. The affected area of the skin frequently itches and may appear reddened.
FIGURE. Seborrheic dermatitis. (From Goldsmith, LA, Lazarus, GS, and Tharp, MD: Adult and Pediatric Dermatology: A Color Guide to Diagnosis and Treatment. FA Davis, Philadelphia, 1997, p 90, with permission.)
The diagnosis is usually made on the basis of the medical history and observation of the characteristic lesions. The disease must be differentiated from psoriasis.
Gentle shampooing with a mild shampoo is helpful in treating cradle cap. Shampoos containing tar, salicylic acid, or zinc pyrithione are often helpful in controlling the scaling. Hydrocortisone creams may be prescribed to relieve redness and itching.
Scrupulous skin hygiene and keeping the skin as dry as possible are essential.
Seborrheic dermatitis is a chronic condition, but the prognosis is good, given effective treatment that controls the disease. The presence of secondary infections may complicate treatment.
There is no known prevention for seborrheic dermatitis.