Phototherapy with narrow band UVB light is used to treat patients with moderate to severe psoriasis or patients who have not responded to topical therapies. This treatment involves exposing the skin to a 311nm wavelength of light called narrow band UVB. Narrow band UVB treatment is administered in a light box in our office, which allows the patient to receive full body light therapy. Patients will generally come in for light treatments three times a week. The light treatments initially only last a short time, usually minutes at first. The length of the light treatment usually increases as treatment progresses. Patients will see clearing of their psoriasis in approximately two months of therapy; however this is dependent on the severity of their psoriasis. Narrow band UVB light therapy is safe and effective. Some side effects of therapy may include sunburns, freckling and photoaging.