Partial response to cyclosporine in a patient with Schnitzler's syndrome

Schnitzler's syndrome is an unusual clinical association of chronic urticaria, intermittent fever and monoclonal immunoglobulin M (IgM) gammopathy. The pathogenesis of the urticaria is unclear and treatment is problematic. We describe the case of a 61-year-old woman with a long history of chronic urticaria with severe pruritus, spiking fever and malaise. The IgM-kappa monoclonal component was detected in the patient's serum 4 years after symptom onset. After ineffective treatment with antihistamines and systemic corticosteroids, oral cyclosporine resulted in complete remission of the fever and malaise, which has persisted after an 18-month follow-up. Partial but maintained remission of the urticaria was also observed, allowing corticosteroid doses to be decreased.