D1.159 - Comorbidity of Asthma in Chronic Spontaneous Urticaria: Prevalence and Immunological Insights from a Sri Lankan Cohort

Chronic Spontaneous Urticaria (CSU) and asthma are immune-mediated conditions driven by shared type 2 inflammatory pathways, involving IgE, mast cell activation, and Th2 cytokines like IL-4 and IL-13. In Sri Lanka, adult asthma prevalence is estimated at 11.8% (95% CI: 10.3%-13.2%) (Gunasekera et al., 2022). Their comorbidity suggests overlapping atopic and autoimmune mechanisms, with antinuclear antibodies (ANAs) potentially indicating autoimmune CSU subtypes that may exacerbate asthma. This study investigates asthma prevalence in CSU patients and the role of immunological markers in a Sri Lankan cohort.

An observational study conducted at the Institute of Allergology and Immunology at the University of Sri Jayewardenepura, Sri Lanka, included 114 patients with CSU (recurrent hives and/or angioedema >6 weeks, no identifiable triggers) from January 2023 to December 2024.Demographic data, ANA patterns(from Indirect Immunofluorescence Testing), and total serum IgE (>100 IU/mL) were extracted from medical records. Statistical analyses included chi-square tests for prevalence comparisons and logistic regression for associations, adjusting for age, sex, and atopy.

Of 114 CSU patients (mean age 43.3 ± 15.1 years, 60% female), 15 (13.2%) had asthma (mean age 46.3 ± 13.2 years, 80% female), comparable to the general Sri Lankan adult population (11.8%, p=0.19). Among asthma-positive patients, 8 (53.3%) were ANA positive for Nuclear patterns, and all 15 (100%) had elevated IgE (>100 IU/mL). Of 83 non-asthmatic CSU patients with ANA results, 42 (50.6%) were ANA positive. ANA positivity showed a modest association with asthma (OR 1.1, 95% CI 0.6-2.2, p=0.74), while elevated IgE was strongly associated (OR 3.5, 95% CI 1.7-7.0, p<0.01).

The 13.2% asthma prevalence in CSU patients aligns with the general Sri Lankan adult population (11.8%), suggesting shared immunological pathways. Comparable ANA positivity (53.3% in asthma-positive vs. 50.6% in non-asthmatic CSU patients) indicates a limited role for ANA in distinguishing asthma comorbidity, while universal elevated IgE in asthma-positive patients highlights type 2 inflammation. These findings support routine asthma screening in CSU patients and targeted management addressing shared inflammatory pathways.