Schnitzler’s syndrome: lessons from 281 cases

Table 1 Strasbourg diagnostic criteria for Schnitzler’s syndrome ¹

Obligate criteria
	Chronic urticarial rash
	Monoclonal IgM or IgG
Minor criteria
	Recurrent fever²
	Objective findings of abnormal bone remodeling with or without bone pain³
	A neutrophilic dermal infiltrate on skin biopsy⁴
	Leukocytosis and/or elevated CRP⁵
Definite diagnosis if
	Two obligate criteria AND at least two minor criteria if IgM, and three minor criteria if IgG
Probable diagnosis if
	Two obligate criteria AND at least one minor criterion if IgM, and two minor criteria if IgG

¹Adopted from Simon et al., Allergy [1].
²A valid criterion if objectively measured. Must be >38°C, and otherwise unexplained. Occurs usually – but not obligatory – together with the skin rash.
³As assessed by bone scintigraphy, MRI or elevation of bone alkaline phosphatase.
⁴Corresponds usually to the entity described as ‘neutrophilic urticarial dermatosis’ (Medicine 2009;88:23–31); absence of fibrinoid necrosis and significant dermal edema.
⁵Neutrophils >10 000/mm3 and/or CRP >30 mg/L.

ISSN: 2045-7022