A Comparison of Chronic Spontaneous Urticaria Clinical Characteristics and Management between Canadian and Israeli Adults.

Introduction: Chronic spontaneous urticaria (CSU) is increasingly recognized as a significant health issue with significant impacts on quality of life in adult populations. Data are sparse regarding differences in clinical characteristics and management of CU in different countries. We aimed to compare adult CU populations in Canada and Israel to identify demographic, clinical, and management differences.

Methods: From 2013 to 2024, Canadian adults with CU were prospectively enrolled at allergy clinics, with clinical data including comorbidities, disease severity (UAS7), control (UCT), and treatment collected. Omalizumab was reserved for refractory cases per guidelines. Israeli adults were recruited from 2009 to 2022 at a dermatology clinic, excluding those with inducible CU or unclear diagnoses. Descriptive statistics and multivariable logistic regression were used to compare demographics and treatment patterns across cohorts using R software.

Results: From 2013 to 2024, 71 adults at the Montreal General Hospital (MGH) and adjutant clinic were diagnosed with spontaneous urticaria, with a median age of 45.8 years (35.2-59.3) and 22.5% male. Between 2009 and 2022, 151 adults at Sheba Hospital were diagnosed with CSU, with a median age of 48.5 years (32.3-60.0) and 32% male. The male prevalence was significantly higher in Israeli CU patients (p < 0.01). Israeli adults had lower reports of comorbidities, including atopic dermatitis (5.3% vs. 19.7%, p < 0.01) and asthma (7.9% vs. 25.4%, p = 0.04). Antihistamine use was higher in Israel (99.3% vs. 85.9%, p < 0.01), along with glucocorticoids (72.8% vs. 14.1%, p < 0.01).

Conclusion: Differences in the demographics, comorbidities, and treatment of CSU may be related to differences between populations and management practices in different countries.