Factors Associated With Omalizumab Response in Chronic Spontaneous Urticaria: Are There Age-Related Differences?

AIM: This study aimed to explore clinical and laboratory markers of omalizumab response in paediatric and adult chronic spontaneous urticaria (CSU) patients. METHODS: The study included 32 children and 67 adults with CSU receiving omalizumab, and 29 paediatric and 30 adult healthy controls; associations with treatment response were evaluated. RESULTS: In adults, higher baseline Systemic Inflammation Response Index (SIRI) (OR = 0.207, p < 0.001), monocyte count (OR = 0.276, p = 0.002), neutrophil-to-lymphocyte ratio (NLR) (OR = 0.455, p = 0.012), and Systemic Immune-Inflammation Index (SII) (OR = 0.487, p = 0.022) were associated with lower odds of treatment response. In paediatric patients, higher baseline SII was significantly associated with lower odds of response (OR = 0.349, p = 0.040). Interaction analyses showed nominally significant age interactions for baseline SIRI (B = -0.169, p = 0.027) and monocyte count (B = -0.193, p = 0.025). During follow-up, SIRI was lower in responders from baseline through 12 months in adults, and at 3 and 6 months in children. SII was lower in responders at baseline in adults, and at baseline, 3, and 6 months in children (all p < 0.05). CONCLUSION: Our findings suggest potential differences in the associations between inflammatory markers and omalizumab response across age groups, though further studies are needed to clarify age-related differences.