Schnitzler's syndrome with monoclonal IgG kappa gammopathy: good response to cyclosporin.

Schnitzler's syndrome (SS) is a rare entity characterized by the association of chronic urticaria and monoclonal IgM gammopathy. Usually, intermittent fever, arthralgia and elevation of erythrocyte sedimentation rate also occur. We report a patient with the same symptoms, but with monoclonal IgG instead of IgM paraproteinaemia. Histological examination of the urticarial lesions showed signs of leucocytoclastic vasculitis. After 20 years of therapeutic failure, cyclosporin has achieved a total clearance of urticarial lesions in our patient. Two previous similar cases with clinical features of SS and monoclonal IgG immunoglobulin have been described. We suggest our case also represents a variant of SS with IgG gammopathy.