Types of Psoriasis
Psoriasis commonly occurs on the scalp, which may cause fine, dry, scaly skin or heavily crusted plaque areas. This plaque may flake or peel off in clumps. Scalp psoriasis may resemble seborrheic dermatitis, but in that condition the scales are greasy and not dry.
Quick GuidePsoriasis: Treatment, Types, and Pictures
What is scalp psoriasis?
Psoriasis is an inflammatory disease of the skin that is estimated to affect about 2.2% of the adult population. Psoriasis causes scaly skin and itching. Some people may have a genetic predisposition to psoriasis. The genes affected seem to be involved with control of the immune system. Psoriasis appears as red scaling, slightly raised bumps (papules) that combine to form plaques. Psoriasis classically appears on the elbows and knees, but it can affect any part of the skin. The scalp is also characteristically affected in many people with psoriasis. Like psoriasis anywhere on the body, scalp plaques produce excess scale and can itch. Severe disease can cause a loss of scalp hair, which usually will return if the disease can be controlled.
Picture of scalp psoriasis. Source: iStock.com.
What is the cause of scalp psoriasis?
It is generally accepted that scalp psoriasis, like all psoriasis, is related to genetic defects that affect certain parts of the immune system. There are undoubtedly environmental factors that trigger its initial development in genetically predisposed individuals. The notion that "emotional stress" plays a causal role or at least exacerbates psoriasis has been difficult to prove. There is no question, however, that psoriasis of the scalp can be an extremely stressful experience.
What are scalp psoriasis symptoms and signs?
Psoriasis appears as a small bump, a papule, surmounted by scale. When these papules coalesce, a plaque is formed that is often covered by thick layers of horny scale. When this scale is shed, it appears as dandruff, which can be quite unsightly. Scratching these plaques, either because of itching or because of the impulse to remove it, is a very poor idea because of what is called the Koebner phenomenon (also known as the Koebner response or isomorphic response). This may cause psoriasis to develop in areas of inflammation and trauma. Scratching off the scale will only make things worse. Occasionally, seborrheic dermatitis of the scalp can be confused with psoriasis since both can produce excess scale and can itch.
Medically Reviewed by a Doctor on 3/17/2016