Definition

Seborrheic dermatitis is a chronic skin condition that causes a scaly, itchy rash. It can appear as a mild, white scaling or a yellowish greasy or reddish scaly rash. Most commonly affected areas are along the hairline, in and behind the ears, and on the eyebrows, around the nose, and chest.

Dandruff is a type of seborrheic dermatitis. It is the scaling of the skin on the scalp. It can be dry or oily and sometimes itchy.

Seborrheic dermatitis involves swelling and redness of the underlying skin (inflammation), while dandruff is just a mild, white scaling of the scalp (no inflammation).

Seborrheic Dermatitis

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Causes

The exact cause of seborrheic dermatitis is unknown, though common skin yeast organisms, called Malassezia, may play a role in some persons. Seborrheic dermatitis seems to run in families and to affect people with oily skin or hair. It may also be associated with other chronic conditions, such as disorders of the immune system and of the nervous system.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. In this case, your risk factors are:

Symptoms

The symptoms of seborrheic dermatitis can vary from mild to severe. They include:

  • Dry or greasy scaling of the scalp
  • Itchy scalp
  • Itchy, scaly rash with small pimples
  • Thickened, flaking skin
  • Reddened skin over the forehead and on either side of the nose

In babies less than one month old, seborrheic dermatitis may cause a thick, yellow, crusted scalp rash known as "cradle cap."

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam. You may be referred to a doctor who specializes in skin disorders (a dermatologist).

Treatment

Treatments for seborrheic dermatitis are usually applied directly to the skin in the form of shampoo or lotion. Treatment depends on the severity of your condition and your symptoms. Treatment can take several weeks or months and may need to be repeated if the condition recurs.

A wide variety of treatments are used for seborrheic dermatitis. These include:

  • Prescription or over-the-counter shampoos containing one or more of the following ingredients:
    • Pyrithione zinc
    • Hydrocortisone or other cortisone (steroid) preparations
    • Selenium sulfide
    • Salicylic acid, sulfur
    • Coal tar
    • Ketoconazole or other antifungal medications
  • Prescription or over-the-counter creams or lotions containing:
    • Hydrocortisone or other cortisone (steroid) preparations
    • Ketoconazole or other antifungal medications
    • Pimecrolimus

Prevention

There are no guidelines for preventing seborrheic dermatitis, because the cause is unknown. If you have seborrheic dermatitis, following treatment guidelines may help prevent a recurrence.