Seborrheic dermatitis may involve the skin of the scalp, eyebrows, eyelids, nasolabial creases, lips, behind the ears, in the external ear, and the skin of the trunk, particularly over the sternum and along skin folds. The cause is unknown.

Seborrheic dermatitis appears to run in families. Stress, fatigue, weather extremes, oily skin, infrequent shampoos or skin cleaning, use of lotions that contain alcohol, skin disorders (such as acne), or obesity may increase the risk.

Neurologic conditions, including Parkinson's disease, head injury, and stroke can also be associated with seborrheic dermatitis. Human immunodeficiency virus (HIV) is also associated with increased cases of seborrheic dermatitis.

Cradle cap appears as thick, crusty, yellow or brown scales over the child's scalp. Similar scales may also be found on the eyelids, ear, around the nose, and in the groin. Cradle cap may be seen in newborns and small children up to the age of 3 years, and is a harmless, temporary condition.

Cradle cap is not contagious, nor is it caused by poor hygiene. It is not an allergy, and it is not dangerous. Cradle cap may or may not itch. If it itches, excessive scratching of the area may cause additional inflammation, and breaks in skin may cause mild infections or bleeding.

• Skin lesions
• Plaques or over large area
• Greasy, oily areas of skin
• Skin scales -- white and flaking, or yellowish, oily, and adherent -- "dandruff"
• Plaques may include the scalp, eyebrows, nose, forehead, or ears
• Itching -- may become more itchy if infected
• Mild redness
• Hair loss may also be associated with this disease

The diagnosis is based on the appearance and location of the skin lesions.

The goal of treatment is to reduce the symptoms.

Flaking and dryness may be reduced by use of over-the-counter "dandruff" or medicated shampoos. Shampoo the hair vigorously and frequently (preferably daily). Loosen scales with the fingers, scrub for at least 5 minutes, and rinse thoroughly. Active ingredients in these shampoos include salicylic acid, coal tar, zinc, resorcin, or selenium.

Shampoos or lotions containing selenium, ketoconazole, or corticosteroids may be prescribed for severe cases. To apply shampoos, part the hair into small sections, apply to a small area at a time, and massage into the skin. If on face or chest, apply medicated lotion twice per day.

Seborrheic dermatitis may improve in the summer, especially after outdoor activities.

For infants with cradle cap:
1. Massage your baby's scalp gently with your fingers or a soft brush to loosen the scales and improve scalp circulation.
2. Give your child daily, gentle shampoos with a mild soap while scales are present. After scales have disappeared, you may reduce shampoos to twice weekly.
3. Be sure to rinse off all soap.
4. Brush your child's hair with a clean, soft brush after each shampoo and several times during the day.
5. If scales do not easily loosen and wash off, apply some mineral oil to the baby's scalp and wrap warm, wet cloths around his head for up to an hour before shampooing. Then, shampoo as directed above. Remember that your baby loses a lot of heat through his scalp. If you use warm, wet cloths with the mineral oil, check frequently to be sure that the cloths have not become cold. Cold, wet cloths could drastically reduce your baby's temperature.
6. If the scales continue to be a problem or concern, or if you child seems uncomfortable or scratches his scalp, contact your physician. He may prescribe a cream or lotion to apply to your baby's scalp several times a day.

Seborrheic dermatitis is a chronic condition, controllable with treatment. It often has extended inactive periods followed by flare-ups.

• Psychological distress, low self esteem, embarrassment
• Secondary bacterial or fungal infections

Call for an appointment with your health care provider if seborrheic dermatitis symptoms do not respond to self-care or over-the-counter treatments.

Also call if patches of seborrheic dermatitis drain fluid or pus, form crusts, or become very red or painful.

The tendency to develop seborrheic dermatitis appears inherited. The severity can be lessened by controlling the risk factors, and by careful attention to skin care (see treatment).