The authors report the case of a 65-year-old man who had an evolving case of Schnitzler's syndrome with lytic bone lesions which was unresponsive to several drugs, and which dramatically improved with small quantities of corticosteroids. Schnitzler's syndrome, first described in 1974, is defined by chronic non-pruritic urticaria, osteocondensation, and monoclonal IgM dysproteinemia without features of lymphoproliferative disease, and is associated with fever, deterioration of the general health and biological signs of inflammation. Only 22 cases of Schnitzler's syndrome have been reported hitherto and there is no known effective treatment, H1 and H2 blockers, dapsone, colchicine, chloroquine, cyclophosphamide, chlorambucil and azathioprine having proven useless in the few patients treated. Corticosteroids may be effective, however, especially against the urticaria.