Schnitzler's syndrome: report of a case with progression to Waldenström's macroglobulinaemia.

Schnitzler's syndrome is a rare but distinct entity in which chronic urticaria is a prominent feature. Our patient presented with an urticarial rash associated with intermittent fevers, lethargy, a migratory polyarthralgia and loss of weight. Skin biopsy revealed a neutrophilic urticaria. An IgM kappa paraprotein was detected on serum protein electrophoresis at a level of 8 g/L (0.6-2.5 g/L). Bone marrow biopsy was normal. Marked improvement of the arthralgia, fever and lethargy was obtained with oral prednisolone. The urticarial rash, however, was only partly responsive. For the next 10 years the patient remained stable but corticosteroid dependent. Over a period of 10 years the IgM paraprotein had slowly risen to 47 g/L. Repeat bone aspirate and trephine revealed a diagnosis of a low grade lymphoplasmacytic lymphoma consistent with Waldenström's macroglobulinaemia. To date, despite six cycles of chemotherapy with oral chlorambucil, his disease remains persistent but stable.