A 33-year-old woman with a 9-year history of psoriasis developed a severe SLE with no signs of visceral involvement during a 3-week exposure to PUVA (psoralen and UVA) therapy. The patient fulfilled the criteria of the American Rheumatism Association (25) for the diagnosis of SLE. She showed dermatological lesions including facial erythema, photo-sensibility arthritis, hematological disorders including leuko-, lympho-, thrombocytopenia, antinuclear antibodies, and dsDNA antibodies. With a therapy that included corticosteroids, chloroquine, and azathioprine the disease could be controlled. The coincidence of a PUVA therapy and the first flare-up of an SLE demonstrates a possible pathogenic role of UV light in SLE.