Schnitzler syndrome associated with hairy cell leukemia presenting with chronic urticaria and arthralgias

Schnitzler syndrome is an underdiagnosed clinical condition characterized by 2 major criteria: chronic recurrent urticarial eruption and monoclonal IgM gammopathy, as well as at least 2 of the following minor criteria: (1) recurrent fever, (2) high C-reactive protein (CRP) levels, (3) signs of abnormal bone remodeling with or without bone pain, and (4) neutrophilic infiltrates on skin biopsy.1 We report the case of a patient with history of hairy cell leukemia who exhibited atypical clinical presentation of chronic urticaria for 2 years before the final diagnosis of Schnitzler syndrome was established.