Seborrheic dermatitis

Seborrheic dermatitis is a condition characterized by discolored, scaly, crusty patches on the skin. The condition typically affects the scalp, but may develop on other parts of the body that have many oil glands.


Causes/associated factors
What causes seborrheic dermatitis is unknown. However, researchers have found that people who have the condition seem to have more of the normal skin yeast Pityrosporum ovale than others. Seborrheic dermatitis is most common in adults and infants younger than age 6 months.
Seborrheic dermatitis often develops in people who have oily complexions, diabetes, AIDS, Parkinson's disease or psoriasis (a skin condition characterized by scaling and itching). It's also common in people who've been hospitalized for serious medical problems. Seborrheic dermatitis tends to be chronic, often coming and going. It doesn't cause hair loss.


Signs/symptoms
Seborrheic dermatitis causes dry or greasy scaling of the skin. Symptoms may be mild or severe, possibly including:
white, slightly yellow, brown or red flaky areas of the scalp, eyebrows, eyelids, armpits, groin, navel, buttocks, sides of the nose, behind or in the ears, over the breastbone, under the breasts, or in the creases between the buttocks
flaky accumulations in the outer ear canal
inflamed eyelids
possible itching
in infants, a stubborn diaper rash that may cause the skin to blister or become red or raw
When seborrheic dermatitis affects an infant's scalp (a condition commonly known as cradle cap), it typically produces thick, yellow or brown scales. When it affects an adult's scalp, it causes redness and fine, flaky scaling of the skin.


Diagnosis
Diagnosis is based on your medical history and a physical exam. Seborrheic dermatitis may look appear similar to or develop in combination with psoriasis. The doctor will examine your rash and note the size of the rash as well as the areas involved to determine whether you have seborrheic dermatitis, psoriasis or both. Skin or blood testing may be done to help identify or rule out other conditions.

Treatment
Depending on the affected area and your age, the doctor may recommend washing with a mild soap and preventing overheating and sweating. Soaking crusts makes them easier to remove. For eyelids, it's often helpful to gently clean them every day with baby shampoo on a cotton swab. Other treatment options may include antiseborrheic shampoos (which may contain salicylic acid, selenium sulfide, pyrithione zinc, coal tar or ketoconazole) and steroid or antifungal creams, ointments, lotions or solutions.

Complications
Seborrheic dermatitis can lead to secondary bacterial infections of the skin, which may require antibiotic treatment. Never use strong topical steroids on the eyelids -- this may cause glaucoma (an eye disease in which the optic nerve is damaged) or cataracts (cloudy areas in the lens of the eye). Embarrassment over your skin's appearance may lead to social isolation.
Severe symptoms that are resistant to treatment are more likely to develop in people who have AIDS, Parkinson's disease, paralysis from a stroke, or neurological disorders that develop after head trauma or spinal cord injury.


Pregnancy-specific information
Pregnancy doesn't increase the risk of developing seborrheic dermatitis. If you have seborrheic dermatitis during pregnancy, treatment measures may differ from those recommended for other adults.

Senior-specific information
Seborrheic dermatitis is more common in people who have Parkin- son's disease and diabetes -- both of which tend to affect older adults. As a general rule, the earlier skin diseases are detected, the easier they may be to treat. Be sure to consult your doctor promptly for any unusual skin changes.