Scalp psoriasis vs. seborrheic dermatitis: What's the difference?

Scalp psoriasis and seborrheic dermatitis of the scalp can be difficult to differentiate. Both are common conditions that affect the scalp. In addition, they share some similar signs and symptoms, such as itchy, red, scaly skin.

Most often, the scales of psoriasis are thicker and somewhat drier in appearance than are the scales of seborrheic dermatitis. In addition, psoriasis usually affects more than one area of the body. If you have scalp psoriasis, you may also have mild psoriasis on your elbows, knees, hands or feet or may notice subtle nail changes, such as pitting.

No single test confirms a diagnosis of psoriasis or seborrheic dermatitis. Your doctor usually makes a diagnosis with a visual examination of the affected skin. Scalp psoriasis and seborrheic dermatitis of the scalp share some similar treatments, including medicated shampoos and topical corticosteroid or antifungal solutions.

Scalp psoriasis is often persistent and more difficult to treat than is seborrheic dermatitis of the scalp. For stubborn cases of scalp psoriasis, your doctor may prescribe oral medications, such as methotrexate (Trexall) or cyclosporine, or combine stronger medications with medicated creams and ointments.