Impact of Omalizumab on Anaphylaxis in Patients Treated for Chronic Urticaria

Background: Anaphylaxis is a life-threatening systemic allergic reaction. Omalizumab (OMA) is an established treatment in chronic urticaria (CU), but experience in anaphylaxis is limited. Objectives: The objective was to evaluate the efficacy and safety of OMA on anaphylaxis in patients with CU who are resistant to antihistamine therapy and have a history of anaphylaxis. Method: Patients with antihistamine-resistant CU and a history of anaphylaxis were eligible. OMA was given 300 mg/150 mg every 4 weeks. Urticaria control test (UCT) scores, the episodes of anaphylaxis, and adverse events were recorded during the OMA treatment. Results: A total of 7 adults were included. After starting OMA, all of them achieved a complete control (UCT = 16) after 3 months of OMA treatment; 6 of them did not suffer any attack of anaphylaxis in the follow-up periods (5 patients for more than 12 months and 1 patient for 4 months). No adverse events were observed. Conclusion: The study indicated the efficacy and safety of OMA for antihistamine-resistant CU patients with a history of anaphylaxis and its potential as a prevention option for anaphylaxis.