Seborrheic dermatitis can occur on many different body areas. Typically it forms where the skin is oily or greasy. Commonly affected areas include the scalp, eyebrows, eyelids, creases of the nose, lips, behind the ears, in the external ear, and along skin folds on the middle of the body.

Seborrheic dermatitis in infants, also called cradle cap, is a harmless, temporary condition. It 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 age 3 .

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.

In general, symptoms of seborrheic dermatitis include:

• Skin lesions
• Plaques over large area
• Greasy, oily areas of skin
• Skin scales -- white and flaking, or yellowish, oily, and adherent -- "dandruff"
• Itching -- may become more itchy if infected
• Mild redness
• Hair loss

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