Seborrheic dermatitis is a common, harmless, scaling rash affecting the face, scalp, ears and other areas where the skin is oily. Dandruff is a form of seborrheic dermatitis located on the scalp. Dandruff presents as scaly white flaky patches scattered within the scalp. Seborrheic dermatitis may appear at any age, even in infancy. In infants, it usually presents as cradle cap, but infantile seborrheic dermatitis may also affect skin creases such as armpits and groin.
Seborrheic dermatitis is common within the eyebrows, on the edges of the eyelids, inside and behind the ears and in the creases beside the nose. It can result in pale pink round or ring shaped patches on the hairline. Sometimes it affects the skin-folds of the armpits and groin, the middle of the chest or upper back. It may or may not be itchy and can be quite variable from day to day. Seborrheic dermatitis is believed to be an inflammatory reaction related to a proliferation of normal skin yeast called Malassezia. The yeast grows on nearly everyone, but some people are susceptible to an overgrowth that can lead to itching and dry, flaky skin. Seborrheic dermatitis is not contagious or related to diet, but it may be aggravated by illness, psychological stress, fatigue, change of season and reduced general health.
Seborrheic dermatitis in adults may be very persistent. However, it can generally be kept under control with regular use of antifungal agents and intermittent applications of topical steroids. Infantile seborrheic dermatitis usually clears up completely before the baby is six months old and rarely persists after one year. Useful treatment options include mild emollients, hydrocortisone cream and topical ketoconazole. For the scalp, medicated shampoos containing ketoconazole, ciclopirox, selenium sulfide, zinc pyrithione, coal tar, and salicylic acid may help. Steroid scalp applications may reduce itching. For the face and body, ketoconazole or ciclopirox cream and topical steroids may help control the itching and inflammation.