Schnitzler's syndrome treated successfully with intravenous pulse cyclophosphamide.

Schnitzler's syndrome is a rare clinical condition characterized by chronic urticaria, intermittent fever, bone pain, arthralgia or arthritis, and monoclonal immunoglobulin M (IgM) gammopathy. Here we describe the case of a 48-year-old Italian female with a long history of arthralgia, leucocytosis, spiking fever, and chronic urticaria with severe pruritus. The IgM-kappa monoclonal component in the serum and bone densification on conventional X-ray with hyperfixation on bone technetium scanning at the distal part of the femurs and at the proximal part of the tibias were detected 4 years after the onset of the symptoms. After many ineffective treatments, the use of pulse cyclophosphamide (CPX) resulted in complete remission of the disease that is still lasting after a 2-year follow-up.