The challenge of omalizumab refractory chronic spontaneous urticaria and the relevance of suspecting Schnitzler syndrome without monoclonal gammopathy

Abstract

Introduction: Schnitzler syndrome (SchS) is a rare autoinflammatory syndrome characterized by chronic urticaria and monoclonal gammopathy (MG). Clinical cases without monoclonal gammopathy have been recorded. Clinical Case: We report on the case of a 43-year-old female with chronic spontaneous urticaria refractory to omalizumab (OMZ) despite a dosage increase (600 mg/4 weeks). Additionally, she developed asthenia and episodes of arthralgias and fever predominantly in the evening. Laboratory re-evaluation revealed elevated inflammatory parameters and skin biopsy showed neutrophilic infiltration. Although MG was absent, SchS was the most likely diagnosis, as other differential diagnoses were excluded. Treatment was started with anakinra, with complete resolution of symptoms. Conclusion: We highlight the importance of specialized urticaria clinics and of reassessing the diagnosis in patients with refractory chronic urticaria. An autoinflammatory disease, such as SchS, could be the diagnosis, even without the presence of monoclonal gammopathy.