Efficacy and Safety of Omalizumab in Patients With Severe Acute Urticaria

Efficacy of omalizumab in chronic spontaneous urticaria had been demonstrated in phase II and phase III studies. Clinical symptoms and signs had been significantly reduced with omalizumab as doses of 150 mg and 300 mg at 4-week intervals in patients with chronic spontaneous urticaria who remained symptomatic despite antihistamine treatment. Omalizumab had an onset of effect within a week after initiation. Thus, the investigators hypothesize that omalizumab will be effective in the treatment of severe acute urticaria as add on therapy with a fast onset of action. Objective:To investigate the efficacy and safety of omalizumab in the treatment of severe acute urticaria Study design: This prospective, interventional, single-arm open label study will recruit patients with severe acute urticaria from emergency departments, hospitalized and outpatient departments. The included patients will receive a single subcutaneous dose of 300mg omalizumab therapy. The efficacy of omalizumab will be evaluated by physical examination and assessed by Urticaria Activity Score (UAS) at baseline, 1 hour, Day 1, Day3, Day 7, and 6 weeks after omalizumab therapy. The frequency and severity of treatment-emergent adverse events will also be evaluated