%0 Case Reports %T Schnitzler syndrome: a case study. %A Sánchez G %A Añó M %A García-Avilés C %A Diéguez I %J J Investig Allergol Clin Immunol %V 10 %N 1 %D Jan-Feb 2000 %M 10780799 %F 8.185 %X Schnitzler syndrome is a clinical entity of unknown etiopathogenesis and is an unusual cause of chronic urticaria. It is characterized by the presentation of a monoclonal band, especially IgM, as well as fever, asthenia and arthralgia. We present the case of a 48-year-old man with 5 years of recurrent urticarial lesions, slight itching, as well as lip, face and occasional pharyngeal edema. The patient had also suffered from fever and right hip and left knee arthralgia. The protein electrophoresis and the immunoelectrophoresis presented an IgG band and a slight lambda band, which is suggestive of a monoclonal gammopathy. The bone marrow examination showed a slight increase in the lymphoplasmatic cells. The marrow biopsy was negative. In order to rule out tumorous, infectious and rheumatic processes as well as collagen diseases, other complementary examinations were performed with negative results. The diagnosis of Schnitzler syndrome as a cause of chronic urticaria requires a thorough study in order to rule out other systemic processes provoking the same symptoms.