Omalizumab-based therapy in normocomplementemic urticarial vasculitis: a retrospective case series of 18 patients

Background Urticarial Vasculitis (UV) is a rare immune-complex–mediated vasculitis characterized by urticarial lesions lasting ≥24 hours and small-vessel inflammation. Management is challenging, and evidence for omalizumab, an anti-IgE monoclonal antibody, remains limited. Objectives To evaluate clinical and laboratory outcomes and safety of omalizumab-based therapy in patients with clinicopathologically diagnosed normocomplementemic UV. Methods This retrospective study included 18 patients with clinicopathologically diagnosed normocomplementemic UV treated with omalizumab. Demographics, disease duration, comorbidities, and laboratory parameters (C-Reactive Protein [CRP], Erythrocyte Sedimentation Rate [ESR], total Immunoglobulin E [IgE]) and Urticaria Activity Score over 7 days (UAS7) were assessed before and after treatment. Results Eighteen patients (14 females, 4 males) with a mean age of 47.3 ± 16.8 years were included. Mean disease duration was 15.8 ± 10.8 months, and mean omalizumab treatment duration was 14.8 ± 12.0 months. Mean UAS7 decreased significantly from 25.3 ± 7.7 to 1.2 ± 3.4 (p < 0.001). CRP also decreased significantly (10.7 ± 17.2 to 3.6 ± 3.3 mg/L; p = 0.002), while the reduction in ESR was not significant (18.2 ± 26.5 to 10.9 ± 7.8 mm/h; p = 0.124). Total IgE increased after treatment (451.6 ± 1075.5 to 496.4 ± 621.2 IU/mL; p = 0.010). Complete remission occurred in 17 patients (94%). No treatment-related adverse events were observed. Study limitations and conclusions Limitations include retrospective design, small sample size, lack of a control group, and concomitant therapies. Omalizumab was associated with marked clinical improvement and favorable safety in normocomplementemic UV, supporting a potential role for IgE-mediated mechanisms.