A 58-year-old woman's 2-year journey with treatment-resistant chronic urticaria led to the diagnosis of Schnitzler syndrome, a rare systemic autoinflammatory disease affecting less than 1% of patients with chronic urticaria, according to a case report.
In the report, published in JAMA, researchers detailed that the patient presented with daily spontaneous wheals, fatigue, arthralgia, myalgia, and intermittent fevers that proved resistant to high-dose antihistamine therapy. While temporary relief was achieved with glucocorticoids, symptoms recurred upon discontinuation.
"Schnitzler syndrome is likely underdiagnosed, and there is an average diagnostic delay of 3.3 years after onset of symptoms," the study authors reported. Just 350 cases have been documented worldwide.
The diagnosis was confirmed through serum immunofixation, which revealed a monoclonal immunoglobulin A gammopathy. A skin biopsy demonstrated dense dermal infiltration of neutrophils without blood vessel involvement.
Treatment with anakinra (100 mg subcutaneously daily) initially resolved the fever and wheals but failed to address persistent arthralgia, myalgia, and fatigue. The patient was subsequently switched to canakinumab (300 mg every 6 weeks), achieving significant improvement.
At 46 months postpresentation, the patient maintained disease control with canakinumab, experiencing only mild intermittent right shoulder arthralgia. Regular monitoring continues as a result of the increased risk of hematologic malignancies associated with the condition.
"Patients with Schnitzler syndrome, similar to those with monoclonal gammopathy of undetermined significance, are at increased risk of hematologic malignancies," the study authors noted. Their research indicated that 12% of patients developed hematologic malignancies over a median follow-up of 8 years, with Waldenström macroglobulinemia accounting for 60% of cases.
The case was reported from the Institute of Allergology at Charité–Universitätsmedizin Berlin, Germany. The authors disclosed receiving various personal fees and grants from pharmaceutical companies.
