There is no known cause for scalp psoriasis, according to WebMD. At least half of all psoriasis patients have psoriasis on the scalp, states the National Psoriasis Foundation.
Psoriasis is a skin condition characterized by red, raised patches with scaly elements, according to WebMD. The condition may be mild, with just a little scaling, but in severe psoriasis cases, the entire scalp can be covered in thick plaque with a crust, according to the National Psoriasis Foundation. The scalp may bleed when these crusts are removed, notes the Mayo Clinic. Symptoms of psoriasis include itching and soreness.
Scalp psoriasis may be treated with special shampoos, or with corticosteroid or antifungal topical treatments, explains the Mayo Clinic. Over-the-counter treatments approved by the U.S. Food and Drug Administration to treat psoriasis contain either salicylic acid or coal tar, states WebMD. In addition to these non-prescription medications, the FDA has approved antimicrobials, topical steroids and vitamin A and D derivatives to treat psoriasis. Treating psoriasis topically can take weeks. After completing treatment, patients often have to maintain their health by shampooing with a medicated product to stave off a recurrence of psoriasis.
For severe cases of psoriasis, drugs called biologics may be prescribed, according to WebMD. These drugs are intended to keep a patient's skin from overproducing new cells and may be given by intravenous infusion or injection. The biologics available to treat psoriasis include alefacept, efalizumab, etanercept and infliximab.