Seborrheic dermatitis is a common inflammatory papulosquamous skin condition that affects areas of the body that are rich in sebum. Sebum is the oily, waxy substance produced and secreted by the body’s sebaceous glands, found mostly on the face, scalp, neck, upper chest and back. Seborrheic dermatitis often presents as an itchy, dry, red, swollen, or greasy appearing rash with white or yellow, crusty scales at the surface. A belief that this is caused by poor hygiene is incorrect.
Cradle cap is a form of seborrheic dermatitis that develops in infancy. Scaly, greasy patches form on the baby’s scalp and, although it looks displeasing to the eye, it is perfectly harmless and often goes away on its own in a few short months.
Seborrheic dermatitis typically affects adults between the ages of 30 and 60 years and is not specific to any gender or race. It often appears on the scalp as “dandruff” and on the eyebrows, external ear canal, upper chest and back, or around the mouth (perioral). This condition is chronic and remissions and exacerbations or “flare-ups” are expected. Numerous factors can contribute to the flare-ups, including cold or dry weather, stress, and underlying medical conditions — specifically diseases that cause the patient to be immunocompromised, such as HIV, or Parkinson’s Disease. It is typically diagnosed on clinical appearance but a skin biopsy may suggest the diagnosis. In family practice, the provider may consider scraping the rash and doing a KOH preparation to rule out tinea, a fungal condition.
How is seborrheic dermatitis treated? This condition can be tricky to treat since the cause is often unknown and there is no cure. These facts should be explained to the patient. The condition waxes and wanes; therefore, education is important about when to restart therapy when signs of exacerbation appear. The goal of treatment is to loosen and remove the scales, reduce the edema and itching, and prevent skin breakdown and infection.
If the affected area is the scalp, there are some over the counter anti-dandruff shampoos that can be effective. These shampoos contain active ingredients like salicylic acid and selenium sulfide to loosen the scales and prevent further buildup. Some of the more popular brands are Neutrogena T/Sal shampoo, Selsun Blue, or Head and Shoulders shampoo. If more intense treatment is required, the dermatologist may prescribe a ketoconazole shampoo to be used 2-3 times per week. The ketoconazole shampoo can also be used on the eyebrows and in a man’s beard. In addition, corticosteroid solutions like Fluocinolone or clobetasol may help with calming the inflammation in the area and decreasing the pruritis often experienced with scalp seborrheic dermatitis.
The steroidal therapies should be limited to a maximum of 2 weeks out of the month to prevent side effects such as atrophy, rosacea, or perioral dermatitis. Topical immunomodulators, such as Tacrolimus 0.1% (Protopic) or pimecrolimus (Elidel) can be prescribed to use in place of the topical steroids and can be used twice daily as needed.