The invention features methods and systems for treating inflammatory, proliferative skin disorders, such as psoriasis, with ultraviolet phototherapy. The methods and systems use optical techniques to scan a patient's skin, designate areas of affected skin, and selectively deliver high doses of phototherapeutic ultraviolet radiation to the designated areas. To insure that only affected areas of skin affected are designated for the high doses of UV radiation, the methods and systems use one or more optical diagnostics that relate to independent physiological features of affected skin.