Modern concepts of the diagnosis and treatment of psoriasis.

Psoriasis is a papulosquamous skin disease that is recognized as one of the most common immune-mediated disorders. At least nine chromosomal psoriasis susceptibility loci have been identified. It is important to emphasize that management of psoriasis begins with identification of the extent of the cutaneous disease. There are three clinical forms of psoriasis, to include psoriasis vulgaris, pustular psoriasis, and erythrodermic psoriasis. Treatments currently available are topical agents used predominantly for mild disease and for recalcitrant lesions in more severe disease, phototherapy for moderate disease, and systemic agents, including photochemotherapy, oral agents, and newer injectable biological agents, which have revolutionized the management of severe psoriasis.