Schnitzler's syndrome: diagnosis, treatment, and follow-up

Abstract Schnitzler’s syndrome is characterized by recurrent urticarial rash and monoclo-nal gammopathy, associated with clinical and biological signs of inflammationand a long-term risk of AA amyloidosis and overt lymphoproliferation. An exten-sive literature review was performed, and the following questions were addressedduring an expert meeting: In whom should Schnitzler’s syndrome be suspected?How should the diagnosis of Schnitzler’s syndrome be established? How should apatient with Schnitzler’s syndrome be treated? How should a patient with Schnit-zler’s syndrome be followed up?. A diagnosis of Schnitzler’s syndrome is consid-ered definite in any patient with two obligate criteria: a recurrent urticarial rashand a monoclonal IgM gammopathy, and two of the following minor criteria:recurrent fever, objective signs of abnormal bone remodeling, elevated CRP levelor leukocytosis, and a neutrophilic infiltrate on skin biopsy. It is considered prob-able, if only 1 minor criterion is present. In patients with monoclonal IgG gamm-opathies, diagnosis is definite if three minor criteria are present and possible iftwo are present. First-line treatment in patients with significant alteration of qual-ity of life or persistent elevation of markers of inflammation should be anakinra.Follow-up should include clinical evaluation, CBC and CRP every 3 months andMGUS as usually recommended.