Psoriasis is common on the scalp. Researchers estimate that at least half (50 percent) of the people who have plaque (plak) psoriasis will have at least one flare-up on the scalp.
What causes scalp psoriasis?
Regardless of where psoriasis forms, the cause is the same. Psoriasis develops when a person’s immune system has faulty signals that tell skin cells to grow too quickly. New skin cells form in days rather than weeks. The body does not shed these excess skin cells. The skin cells pile up on the surface of the skin, causing patches of psoriasis to appear.
Scalp psoriasis can be very mild, with slight, fine scaling. It can also be very severe with thick, crusted plaques covering the entire scalp. Psoriasis can extend beyond the hairline onto the forehead, the back of the neck and around the ears.
Other skin disorders, such as seborrheic dermatitis, may look similar to psoriasis. However, scalp psoriasis appears powdery with a silvery sheen, while seborrheic dermatitis appears yellowish and greasy.
