Clinical characteristics, type 2 comorbidities, and treatment responses in pediatric and adult chronic spontaneous urticaria: A multicenter retrospective cohort study

Background: Chronic spontaneous urticaria (CSU) presents with unpredictable, often debilitating symptoms, yet detailed clinical characterization, particularly in pediatric populations, remains limited. Improved understanding of clinical profiles and comorbidities may guide management strategies. Objective: The objective was to characterize clinical presentation, comorbid type 2 inflammatory diseases, and treatment responses in a large cohort of pediatric and adult patients with CSU across multiple allergy practices. Methods: A retrospective observational cohort study was conducted across four U.S. allergy clinics, including two pediatric- and two adult-focused practices. Medical records of 400 patients with CSU (189 pediatric patients, 211 adults) with ≥ 6 months of follow-up between 2013 and 2023 were reviewed for demographic data, comorbidities, clinical presentation, clinician-documented disease severity, and treatment outcomes. Results: Disease severity spanned mild (24%), moderate (28%), and severe (48%) disease; adults more often presented with severe disease (65% versus 32% in pediatric patients). Atopic comorbidities were common, including allergic rhinitis (72%), asthma (38%), and atopic dermatitis (17%), with 43% of patients having two or more type 2 inflammatory comorbidities. H 1 -antihistamines were the most frequently used therapies, with cetirizine being most common. Omalizumab showed effectiveness in most patients, although ∼31% experienced partial or no response. Systemic corticosteroids and cyclosporine were used infrequently. Sparse documentation of physical findings and laboratory analysis limited further objective analysis. Conclusion: This U.S. multicenter study highlights the substantial burden of atopic disease and refractory CSU in both pediatric and adult populations. These findings emphasize the need for prospective studies with standardized clinical documentation to better understand CSU phenotypes and optimize individualized treatment strategies.