Efficacy and safety of treatment modalities for psoriasis.

Although there is no cure for psoriasis, a variety of treatments are available to reduce the severity of symptoms and lessen their impact on the patient's quality of life. For patients with less than 20% body surface involvement, topical therapy is the most appropriate choice for initial treatment. Commonly used topical therapies include corticosteroids; calcipotriene, a vitamin D analogue; tazarotene, the first retinoid to be approved for the treatment of psoriasis; and anthralin. Each of these treatments is effective in mild to moderate psoriasis, but each is also associated with varying degrees of safety and tolerability concerns. For patients with more severe, recalcitrant, or extensive psoriasis, phototherapy and systemic therapies are available. These therapies are more effective than topical therapy, but are also associated with significant cutaneous and systemic adverse effects. Phototherapy, alone or in combination with coal tar or psoralen, is very effective in the treatment of moderate to severe psoriasis, but can lead to erythema and pruritus acutely, and long-term problems such as wrinkling, solar elastosis, and an increased risk of skin cancer. Systemic therapies such as acitretin, methotrexate, cyclosporine, hydroxyurea, and thioguanine are also very effective in the treatment of moderate to severe psoriasis, but are all associated with significant systemic toxicity, which requires that patients be monitored carefully. Ultimately, treatment selection for each patient must take into account both the patient's disease severity and expectations for improvement, as well as the risk-benefit ratio associated with each potential therapy.