Abstract / Summary
Background/Objectives: Relapse after omalizumab withdrawal is common in chronic spontaneous urticaria (CSU), but patients requiring repeated treatment re-initiation across successive withdrawal cycles remain poorly characterized. This study aimed to characterize patients with repeated relapse requiring omalizumab re-initiation and to determine whether routinely available baseline parameters could distinguish them from other patients with CSU. Methods: This retrospective, single-center study included 46 adults with CSU who achieved disease control with standard-dose omalizumab after an initial 6-month course. Patients were evaluated during a fixed 12-month period following the first withdrawal. Repeated omalizumab re-initiation was defined as relapse requiring re-initiation within 12 weeks after withdrawal on at least two occasions. Baseline clinical and laboratory characteristics were compared between groups, and multivariable logistic regression was performed. Results: Twenty-nine patients (63.0%) met the criteria for repeated omalizumab re-initiation. Baseline disease activity, angioedema, atopic status, autoimmune thyroid disease, previous systemic corticosteroid use, total immunoglobulin E (IgE), anti-thyroid peroxidase antibody (anti-TPO), C-reactive protein (CRP), eosinophil and basophil counts, and inflammatory indices did not differ significantly between the repeated-treatment and comparison groups. Vitamin B12 was the only laboratory parameter showing a significant between-group difference in univariable analysis (259 vs. 335 pg/mL; p = 0.034); however, this association was not retained after multivariable adjustment. None of the variables included in the multivariable model were independently associated with repeated omalizumab re-initiation. Conclusions: Repeated relapse requiring omalizumab re-initiation across successive withdrawal cycles was common during the 12-month observation period. Routinely available baseline clinical and laboratory parameters did not reliably distinguish patients who developed this relapse–retreatment pattern. These findings highlight the difficulty of predicting repeated retreatment requirements from conventional baseline assessments and support further prospective investigation of individualized withdrawal and step-down strategies in patients who develop recurrent relapse–retreatment cycles.