Epidemiology & pathophysiology

Schnitzler syndrome

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Epidemiology & pathophysiology

Epidemiology

Frequency

More than 90 cases have been reported. The vast majority of reported patients were from Europe, especially France. In the last decade, however, additional cases have been described by Japanese, Israeli, American, Canadian, as well as Australian authors.

Race

Most cases were Caucasians, but two Japanese cases are known as well. No cases of African origin have been reported to date. Still, no conclusions can be drawn from these data as only few doctors are familiar with Schnitzler syndrome.

Sex

Affected males are reported 1.6 times as often as females, comprising 50 out of 80 cases.

Age of onset

The mean age of onset is 52 years. In only 4 patients symptoms started before the age of 40 years, one of them at the exceptional young age of 12 years.

Due to a significant doctor’s delay, the average age at diagnosis is more than 6 years higher.

Pathophysiology

The pathophysiology of the Schnitzler syndrome is unknown. Several hypotheses have been formulated. First, there could be a role for the monoclonal antibodies in generating the rash. IgM-κ antiskin autoantibodies were demonstrated by Western blotting on epidermal extracts. Monoclonal IgM deposits were shown in the skin along basement membranes or in capillary walls in about 25 % of patients. [Lipsker 2001]

Another option is that certain cytokines play a major role in the pathophysiology. Levels of IL-6, GM-CSF and G-CSF have been mentioned occasionally, but IL-1 is thought to be much more of a key player. Amongst others, this theory is supported by the observation of the induction of complete remission after the administration of an IL-1 receptor antagonist in 6 out of 6 cases.

For references see literature page

Last update: June 30, 2007