What is it?

Seborrheic dermatitis is the cause of common dandruff. It has been attributed to Malassezia furfur, a yeast that is commonly found on the scalp, but the cause is not completely understood. It appears most commonly in areas where there are large numbers of sebaceous glands such as the scalp, face, and chest.

What does it look like?

In newborns it presents as cradle cap and can be quite widespread including the diaper area. It causes widespread erythematous papules with occasional scale and can be difficult to differentiate from atopic dermatitis. Involvement of the diaper area in seborrheic dermatitis is a good clue. In older children, seborrheic dermatitis can present with mild itching and flaking on the scalp. In more severe cases, erythematous scaly plaques with a yellow-greasy scale are most commonly seen in the scalp, eyebrows, and nasal ala.

How is it treated?

Seborrheic dermatitis is treated with a combination of corticosteroids and anti-seborrheic shampoos. For facial involvement, hydrocortisone is usually sufficient to control the erythema. The combination of hydrocortisone with 2% ketoconazole cream is a common prescription that is safe for all ages. For eyebrows and scalp, a liquid form of corticosteroid, such as fluocinolone oil or betamethasone scalp solution, is often easier to apply. Anti-dandruff shampoos are also useful and may be anti-inflammatory, keratolytic or have anti-yeast properties. All anti-dandruff shampoos must be left on for 5-10 minutes before rinsing. For patients with thick scale, application of an oil such as mineral oil to the area overnight (with a shower cap to increase the effect of the oil and prevent staining sheets) with a shower in the morning is effective in removing the thick scale.