Related Experiment Videos
Omalizumab-Associated Post-Injection Urticaria Exacerbation and Urticaria-Related Adverse Reactions During Treatment
Weeratian Tawanwongsri1,2, Pitchaya Jaruvijitrattana3, Chime Eden4
1Division of Dermatology, Department of Internal Medicine, School of Medicine, Walailak University, Nakhon Si Thammarat 80160, Thailand.
Background/Objectives:
Omalizumab is an effective treatment for antihistamine-refractory chronic urticaria. However, post-injection urticaria exacerbation and related adverse reactions remain inconsistently reported. This scoping review mapped evidence on clinical presentation, timing, mechanisms, management strategies, rechallenge outcomes, treatment discontinuation, and patient outcomes associated with these reactions.
Methods:
The review followed the Joanna Briggs Institute methodology and was registered prospectively in INPLASY (INPLASY202650060). PubMed, Scopus, and the Directory of Open Access Journals were searched from inception to April 2026. Eligible studies included English-language case reports, case series, observational studies, cohort studies, registry or pharmacovigilance studies, postmarketing surveillance studies, and clinical trials reporting urticaria-related or hypersensitivity-type adverse reactions during omalizumab treatment for chronic urticaria. Data were charted descriptively and synthesized narratively.
Results:
Seventeen studies published between 2015 and 2026 included 2790 patients with chronic urticaria, 60 of whom experienced urticaria-related adverse reactions, corresponding to a mapped proportion of 2.2%. Clinical phenotypes included transient urticaria exacerbation, urticaria flare or worsening, localized urticarial plaques at the injection area, angioedema, anaphylaxis or anaphylaxis-like reactions, and serum sickness-like reactions. Reactions occurred within minutes to several hours, within 24 h, several days, or up to 1 week after injection or dose escalation. Reactions occurred following the first dose, repeated doses, and dose escalation. Proposed mechanisms included delayed hypersensitivity, possible IgE-mediated delayed-onset anaphylaxis, serum sickness-like reaction, paradoxical worsening, infection-associated flare, excipient-related reactions, and severe underlying CSU exacerbation mimicking anaphylaxis. Management strategies ranged from observation or symptomatic treatment to discontinuation of omalizumab and systemic interventions.
Conclusions:
Omalizumab-associated urticaria-related adverse reactions were infrequently reported across the mapped evidence but were clinically heterogeneous. Standardized definitions and detailed case reporting are needed to clarify causality, recurrence risk, rechallenge safety, and long-term outcomes.
