The incidence and severity of disease seem to be affected by genetic factors, emotional or physical stress, and climate (usually worse in cold weather) or HIV may have severe dermatitis

Symptoms and signs

• Dermatitis is usually apparent only as dry or greasy diffuse scaling of the scalp (dandruff) with variable pruritus
• In severe disease, yellow-red scaling papules appear along the hairline, behind the ears, in the external auditory canals, on the eyebrows, in the axillae, on the bridge of the nose, in the nasolabial folds, and over the sternum
• Marginal blepharitis with dry yellow crusts and conjunctival irritation may develop
• Seborrhic dermatitis does not cause hair loss

Neonatal seborrhic dermatitis

Newborns may develop seborrhic dermatitis with a thick, yellow, crusted scalp lesion (cradle cap); fissuring and yellow scaling behind the ears; red facial papules; and stubborn diaper rash.

Older children may develop thick, tenacious, scaly plaques on the scalp that may measure 1 to 2 cm in diameter.

Treatment

• In adults, zinc pyrithione, selenium sulfide, sulfur and salicylic acid, or tar shampoo should be used daily or every other day until dandruff is controlled and twice/wk thereafter
• A corticosteroid lotion (eg, 0.01% Fluocinolone solution, 0.025% Triamcinolone lotion) can be rubbed into the scalp or other hairy areas bid until scaling and redness is controlled.
• Seborrhic dermatitis of the postauricular areas, nasolabial folds, eyelid margins, and bridge of the nose, 1% hydrocortisone is rubbed in bid or 3 times a day, decreasing to once/day when controlled.
• In some patients, 2% ketoconazole cream 2 times a day for 1 to 2 wk induce a remission that lasts for months.

In infants, a baby shampoo is used daily, and 1% hydrocortisone cream is rubbed in bid.

For thick lesions on the scalp of a young child, 2% salicylic acid in olive oil or a corticosteroid gel is applied at bedtime to affected areas and rubbed in with a toothbrush. The scalp is shampooed daily until the thick scale is gone.