PSORIASIS affects approximately 3% of the population. It has been treated with topical steroids, tar or tar derivatives alone or in combination with ultraviolet B light, or photosensitizing psoralen compounds in combination with ultraviolet A light. Oral antimetabolites may be effective but are associated with deleterious side effects. So far, to our knowledge, three patients with severe psoriasis have responded to dialytic therapy.1,2 A fourth patient had intractable psoriasis that resolved during the course of hemodialysis. Report of a Case A 51-year-old woman was hospitalized at the University of Minnesota Hospitals with renal failure secondary to polycystic kidney disease. She complained of fatigue, lethargy, weakness, anorexia, and some nausea associated with her renal disease. Her skin problems had begun 16 years earlier when she noted scaling on her face and scalp that gradually progressed to involve the nose, ears, neck, buttock, abdomen, and knees. Two of the nails of