Prevalence of autoimmunity in patients of chronic urticaria – A cross-sectional pilot study from Eastern India

Objectives: Chronic spontaneous urticaria (CSU) is a common skin disorder with a daily or near-daily occurrence of hives and angioedema for over 6 weeks. CSU is classified into two endotypes: autoallergic and autoimmune. Autoimmunity, particularly the presence of autoantibodies, is linked to unresponsive cases. In India, the prevalence and characteristics of CSU are poorly understood. This research aims to investigate the prevalence of autoimmunity and the clinico-epidemiological profile of CSU in an eastern Indian healthcare institution, expecting to find autoimmunity as a significant factor impacting disease severity. Material and Methods: A hospital-based observational cross-sectional study was conducted to examine the prevalence of autoimmunity in 30 patients with CSU in eastern India. Patients aged 18 and above, diagnosed with CSU, were included. Data collection involved clinical assessments, urticaria activity score (UAS7) for disease activity, the autologous serum skin test (ASST), and various laboratory tests for autoantibodies and related factors. The prevalence of autoimmunity was calculated, and statistical analyses were performed using appropriate tests. Ethical clearance and informed consent were obtained in accordance with ethical guidelines. Results: In our study of 30 patients, we employed descriptive and inferential statistics for analysis. Demographically, the mean age was 30.6 years, with an average urticaria duration of 18.46 months and an age of onset of 28.56 years. The study included 20 females, comprising 67% of the population, with the remaining participants being males. Around 22 patients (73%) had CSU, while the remaining 8 patients (27%) had chronic inducible urticaria. Regarding the prevalence of autoimmunity, 10 (33.3%) of patients had at least one positive autoantibody, indicating autoimmune CSU. The most common autoantibody was anti-thyroid peroxidase (40%), followed by Antinuclear antibody (20%), rheumatoid factor (10%), and others (30%). Autoimmune CSU was associated with higher C-reactive protein levels and lower serum immunoglobulin E (IgE) levels than autoallergic chronic urticaria. In addition, patients with angioedema had more severe disease, as indicated by higher UAS7 scores. Type 1 autoallergic CSU had significantly higher serum IgE levels compared to type 2b autoimmune CSU. Angioedema was significantly associated with ANA positivity and the type 2b autoimmune CSU but not with ASST. Conclusion: In summary, our pilot study sheds light on the prevalence and endotypic diversity of CSU in India. Autoimmunity emerges as a frequent contributor to CSU in our population, significantly impacting disease severity. These findings underscore the necessity for standardized diagnostics and accessible methods for autoimmune CSU and the development of tailored treatments. Further research should validate and expand our results, delving into potential therapeutic implications.