Treatment of severe psoriasis with systemic drugs.

: Psoriasis, a common papulosquamous skin disease of unknown cause, affects 2% of the U.S. population with 150,000-200,000 new cases annually. Systemic drug treatment of severe psoriasis includes retinoids, methotrexate, cyclosporine, hydroxyurea, sulfasalazine, and calcitriol. It is important for dermatology nurses to understand the effects of these medications when treating patients who have severe psoriasis.