Predictors of Treatment Response to Omalizumab in Children with Chronic Spontaneous Urticaria: A Real World Study

BACKGROUND: Omalizumab is an effective therapy for H1-antihistamine-refractory chronic spontaneous urticaria (CSU). However, predictive biomarkers for treatment success in the pediatric population remain poorly defined. This study aimed to identify clinical and laboratory factors predicting complete disease control in children receiving omalizumab. METHODS: We conducted a retrospective cohort study of 44 pediatric patients (aged 12-18 years) with CSU treated with omalizumab (300 mg/4 weeks). Disease activity and control were assessed using Urticaria Activity Score (UAS7), Urticaria Control Test (UCT), and Chronic Urticaria Quality of Life Questionnaire at baseline and months 1, 3, and 6. Complete control was defined as UAS7=0 and UCT=16 at month 6. Univariate and multivariate logistic regression analyses were performed to identify independent predictors. RESULTS: Complete control was achieved in 40.9% (n=18) of patients at month 6. In multivariate analysis, shorter symptom duration prior to omalizumab (OR: 0.46; 95% CI: 0.25-0.88) and higher baseline absolute eosinophil count (OR: 1.04; 95% CI: 1.00-1.06) were identified as independent predictors of complete control. In addition, early clinical response at month 1 was significantly associated with subsequent treatment success and may serve as an early on-treatment prognostic marker. CONCLUSION: Early initiation of omalizumab and higher baseline eosinophil counts are strong predictors of complete disease control in pediatric CSU. These findings support a biomarker-guided and timely intervention strategy to optimize clinical outcomes in children.