Excerpt from Schnitzler Syndrome

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Background

Schnitzler syndrome (SS), first reported in 1972, is characterized by chronic, nonpruritic urticaria in association with recurrent fever, bone pain, arthralgia or arthritis, and a monoclonal immunoglobulin M (IgM) gammopathy in a concentration that is usually less than 10 g/dL. Since 1972, approximately 50 cases have been reported.

Pathophysiology

The exact pathogenesis of SS is unclear. Some hypothesize that the deposition of the IgM paraprotein, leading to the formation of immune complexes and the activation of the complement cascade, is responsible for the cutaneous manifestations. Another proposed mechanism involves the uncontrolled activation of interleukin 1-alpha (IL-1alpha).

Frequency

United States

Only a few cases have been reported from the United States.

International

SS is rare, with approximately 50 cases reported in the literature. The original case was from France, with most cases from the same country. The vast majority of cases come from Europe.

Mortality/Morbidity

Most patients with SS have a chronic benign course. Spontaneous remissions have not been reported. Approximately 10-15% of patients eventually develop a lymphoproliferative disorder, either a lymphoplasmacytic lymphoma, Waldenström macroglobulinemia, or IgM myeloma. Schnitzler's original patient died at age 88 years, with a diffuse lymphoplasmacytic infiltration of his liver and bone marrow. Thus, the initial workup of a patient with SS should include an examination of the bone marrow, immunoelectrophoresis of serum, and a urinary protein level. A lymph node biopsy should be performed if the nodes are enlarged.

Race

The race distribution is not known.

Sex

Males have a slight predominance.

Age

Patients with SS have ranged from age 29-71 years at the time of diagnosis. The average age of onset is approximately 55 years.

Please click here to view the full topic text: Schnitzler Syndrome