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, on the eyebrows, around the nose, and on the chest.

Dandruff is a type of seborrheic dermatitis where there is a scaling of the skin on the scalp. The area can be dry or oily, and is sometimes itchy.

Seborrheic Dermatitis

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Causes

The exact cause of seborrheic dermatitis is unknown. Common skin yeast organisms or genetic factors may play a role for some people.

Risk Factors

Factors that may increase the chances of seborrheic dermatitis:

• Family members with seborrheic dermatitis
• Chronic conditions, including disorders of the immune system such as HIV infection
• Neurological conditions, such as Parkinson disease or, less commonly, stroke

Symptoms

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

• Dry or greasy, scaling of the scalp
• Itchy scalp
• Itchy, scaly rash with small pimples on nasal folds, eyebrows, anterior chest, upper back, arm pits, or genitals
• Thickened, flaking skin
• Reddened skin over the forehead and on either side of the nose

In babies less than 1 month old, seborrheic dermatitis may cause a thick, yellow, crusted scalp rash known as cradle cap.

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done. The diagnosis is made by the appearance of the rash.You may be referred to a doctor who specializes in skin disorders.

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 symptoms. Seborrheic dermatitis in infants will usually resolve on its own.

Prevention

There are no current guidelines to prevent seborrheic dermatitis because the cause is unknown.