Narrowband UVB Phototherapy in the Treatment of Psoriasis Vulgaris

Inclusion Criteria: * Signed informed consent. * History of chronic plaque psoriasis vulgaris, for at least six months. * ≥10% body surface affected * Age 18 or greater. * Concomitant, chronic, but well-controlled medical conditions such as hypertension are allowable. * No treatment with topical steroids for at least 2 weeks prior to entering the study * No treatment with systemic therapies, including etretinate, UVB, PUVA, or cyclosporine, other biologics 4 weeks prior to entering the study. However, if a patient is considered to be "unstable", or would deteriorate clinically if the systemic agent is ceased (eg efalizumab), a shorter "washout" period may be considered, and would be documented in the patient charts. * Patients who receive a stable dose of methotrexate (defined as \<15mg/week for 4 months or greater) for psoriatic arthritis may be included. Exclusion Criteria: * Subjects who do not meet the above criteria, or who meet any of the following criteria: * Guttate, erythrodermic, or pustular psoriasis as sole or predominant form of psoriasis. * PHOTOSENSITIVITY: Hypersensitivity to sunlight or UVB light of any type; history of Lupus, PMLE, or any disease known to be worsened by UV light exposure * A history of non-melanoma skin cancer may be acceptable, and in this situation, the patient will be carefully evaluated. * Poorly controlled medical conditions of any kind. * Any medical condition that, in the opinion of the Investigator, would jeopardize the health or well being of the patient during the course of this study.