Schnitzler syndrome: a rare cause of difficult to treat chronic urticaria

Abstract

Schnitzler syndrome is a rare cause of urticaria and is defined by monoclonal gammopathy and chronic urticaria or urticarial vasculitis combined by at least two of the following features: fever, arthralgia or arthritis, bone pain, hepato-and/or splenomegaly, palpable lymph nodes, elevated erythrocyte sedimentation rate, and leukocytosis. Although the pathophysiology is not completely evaluated, it usually presents with resistance to corticosteroids and many patients respond to anakinra, an IL-1 receptor antagonist. The mean age of onset is 51, but very few cases have been documented in elderly patients. Here we describe a 79-year-old woman diagnosed as Schnitzler syndrome who fulfilled the diagnostic criteria of the syndrome with multiple mediastinal lymph nodes, fever and arthralgia, bone pain, elevated erythrocyte sedimentation rate, urticarial vasculitis and a IgG kappa monoclonal gammopathy of undetermined significance. On capillary serum protein electrophoresis of the patient with the Capillarys System, the morphology of the.-region was disturbed. Although there wasn't any obvious monoclonal peak on Capillarys (immunotyping), the result was diagnosed as an IgG kappa type monoclonal immunoglobulin. For the confirmation of our finding we performed immunofixation electrophoresis which is accepted as the gold standard method for the characterization of monoclonal proteins, although it failed to detect an IgG kappa type band. Both kappa and lambda free light chain concentrations were within the reference range, however the kappa/lambda ratio was abnormal. The patient initially responded well to corticosteroids, but later needed to be treated with azathioprine as a corticosteroid sparing drug. After total clinical improvement methylprednisolone was discontinued with tapering and azathioprine was kept on. At the end of 3 months of therapy, she was accepted to be in clinical remission. During her follow up she has remained in remission approximately for a year with the low dose of azothiopurine.