RESUMEN
Psoriasis is a chronic, genetically determined skin disease. A variety of biochemical and molecular biological alterations have been identified, but the pathogenesis of psoriasis is still not clear. For patients with mild to moderate psoriasis, topical therapies are generally used. However, approximately one-third of the patients have a moderate to severe psoriasis and need a systemic therapy. Beside well known therapeutical approaches, e.g. PUVA, retinoids, ciclosporine A, methotrexate or fumaric acid derivatives, innovative therapeutical strategies have been developed recently. Fusion proteins [e.g. alefacept, denileukin diftitox, etanercept], monoclonal antibodies [e.g. adalimumab, efalizumab, infliximab] or enzyme inhibitors [e.g. mycophenolate mofetil] have been successfully used in the treatment of patients with severe psoriasis and/or psoriatic arthritis