Psoriasis and Topical Iranian Traditional Medicine.

Background: Psoriasis is a common chronic inflammatory skin, nails, and joints disease related to the immune system by periods of exacerbations and remissions. It is characterized by thick end, erythematous, and scaling lesions, which affects about 2 to 4 percent of the general population. The disease occurs equally in both sexes and the most common form of the disease is psoriasis vulgaris.