Schnitzler's syndrome: report of a new case and a review of the literature.

Schnitzler syndrome is a rare condition characterized by chronic non-pruritic urticaria, recurrent fever, bone pain, osteocondensation, and monoclonal IgM gammopathy without features of lymphoproliferative disease. We describe the case of a 44-year-old man with an 8-year history of bone pain with hyperostosis and a 5-year history of chronic non-pruritic urticaria, associated with fever, hyperleukocytosis, hepatomegaly, serum monoclonal IgM-kappa. Systemic treatment with steroids was effective against bone pain but was ineffective in controlling the urticaria. We also review 35 cases. No adequate treatment has yet been found. The pathogenesis is unclear and the role of the IgM component in the induction of urticaria has not been established.