Association between Clinico-Epidemiological Features in Chronic Urticaria with Autologous Serum Skin Test: A Cross-sectional Observational Study

Introduction: Urticaria is a frequent and heterogeneous skin disease characterised by the development of wheals (hives), angioedema, or both. Chronic urticaria is characterised by the occurrence of wheals lasting less than 24 hours, with or without angioedema occurring daily or almost daily lasting more than six weeks. The two subtypes of chronic urticaria are Chronic Spontaneous Urticaria (CSU) and Chronic Inducible Urticaria (CIU). Autologous Serum Skin Test (ASST) is the simplest and the best in-vivo clinical test for the detection of basophil histamine-releasing activity. ASST has a sensitivity of approximately 70% and a specificity of 80%. Aim: To study the association between clinico-epidemiological features of CSU with positive and negative ASST. Materials and Methods: The cross-sectional study was conducted on 80 clinically diagnosed cases of CSU attending the Department of Dermatology Venereology Leprology Out Patient Department at Mahatma Gandhi Memorial Hospital (Kakatiya Medical College), Warangal, Telangana, India; during the period of January 2016 to September 2017. The detailed history was taken; complete physical and cutaneous examination and laboratory investigations like Complete Blood Picture (CBP), Absolute Eosinophil Count (AEC), Erythrocytic Sedimentation Rate (ESR), Thyroid Function Test (TFT) were carried out. ASST was done and read after 30 minutes. Chi-square test was applied and the results analysed using Statistical Package for the Social Sciences version 10.0. Results: Out of total 80 patients included in the study, ASST was positive in 36 (45%) and negative in 44 (55%). ASST positive patients showed longer duration of the disease with increased frequency of attacks and longer duration of wheals. However, both ASST positive and negative groups did not show statistically significant difference in the age of occurrence, gender, angioedema, dermographism. Conclusion: Autoimmune urticaria has no distinctive clinical features. ASST positive, autoimmune urticaria patients have more severe disease with greater impact on quality of life. Thus, they may need more aggressive treatment.