Five patients with chronic renal failure who were undergoing maintenance hemodialysis developed a self-limited bullous dermatosis restricted to light exposed areas, primarily involving the dorsa of the hands. Porphyrin levels and phototesting were normal, but histologic sections of the bullae showed thickening of venule walls, hypogranulated mast cells, and perivenular deposition of immunoglobulins. This combination of features has not previously been described and may reflect a pathologic process unique to chronic hemodialysis.