Table 1

Diagnostic criteria of the Schnitzler syndrome

Urticarial skin rash1,2 and monoclonal IgM component3 and at least 2 of the following criteria4:


Fever


Arthralgia or arthritis


Bone pain


Palpable lymph nodes


Liver or spleen enlargement


Elevated ESR


Leukocytosis


Abnormal findings on bone morphologic investigations


Another cause must be eliminated in all cases (see differential diagnosis), most notably hyper IgD syndrome, adult onset Still disease, urticarial hypocomplementemic vasculitis, acquired C1 inhibitor deficiency and cryoglobulinemia.

1: the urticarial skin rash has now been extensively described and corresponds nosologically to a neutrophilic urticarial dermatosis [9]

2: some authors have reported patients with all signs of the Schnitzler but without the typical skin rash [8]; though those patients have probably a very similar disease, until further characterization, the peculiar skin rash should remain an obligate diagnostic criteria.

3: Some patients have a monoclonal IgG component instead of a monoclonal IgM [reviewed in [3]]

4: In patients treated with IL-1 inhibitors, a rapid and immediate response is supportive of the diagnosis. In case of unresponsiveness to anakinra, the diagnosis should be reconsidered.

Lipsker Orphanet Journal of Rare Diseases 2010 5:38   doi:10.1186/1750-1172-5-38

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