Seborrheic dermatitis is a common, inflammatory skin condition that causes flaky, white to yellowish scales to form on oily areas such as the scalp, face or inside the ear.
It can occur with or without reddened skin.
Cradle cap is the term used when seborrheic dermatitis affects the scalp of infants.
Risk factors include:
- Stress or fatigue
- Weather extremes
- Oily skin, or skin problems such as acne
- Infrequent shampoos or skin cleaning
- Using lotions that contain alcohol
- Neurologic conditions, including Parkinson's disease, head injury or stroke
- Human immunodeficiency virus (HIV)
The exact cause of seborrheic dermatitis is unknown. Doctors think it may be due to a combination hormone levels, weakened immune system, lack of certain nutrients, or nervous system problems. Irritation from a yeast called Malassezia may also lead to this condition. Seborrheic dermatitis appears to run in families.
Seborrheic dermatitis can occur on different body areas. Usually, it forms where the skin is oily or greasy. Common areas include the scalp, eyebrows, eyelids, creases of the nose, lips, behind the ears, in the outer ear, and middle of the chest.
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 sticky dandruff
- Itching -- may become more itchy if infected
- Mild redness
- Hair loss
Diagnosis is based on appearance and location of the skin lesions. Further tests, such as skin biopsy, are rarely needed.
Flaking and dryness can be treated with over-the-counter dandruff or medicated shampoos. You can buy these at the drugstore without a prescription. Look for a product that says on the label it treats seborrheic dermatitis. Such products contain ingredients such as salicylic acid, coal tar, zinc, resorcin, ketoconazole, or selenium sulfide. Use the shampoo according to label instructions.
For severe cases, your healthcare provider will likely prescribe a shampoo or lotion containing a stronger dose of selenium sulfide, ketoconazole, or corticosteroid. A cream that contains an immunomodulator may be prescribed. This medicine suppresses the immune system to treat inflammation.
It is thought that sunlight improves seborrheic dermatitis. In some persons the condition gets better in the summer, especially after outdoor activities.
Seborrheic dermatitis is a chronic condition that comes and goes and can be controlled with treatment.
Severity of seborrheic dermatitis can be lessened by controlling risk factors and paying careful attention to skin care.