Autologous serum skin test in chronic spontaneous urticaria and its correlation with biochemical markers- A descriptive study from a tertiary hospital of North India

Abstract

Autoimmune urticaria (AIU) is an important subset of chronic spontaneous urticaria (CSU) and can be relatively difficult to manage. Autologous serum skin test (ASST) has served as a useful bedside test to detect AIU and its comparison with various blood biomarkers may unlock avenues in diagnosing autoimmune urticaria. Aim of our study was to assess role of ASST in CSU and its correlation with relevant biomarkers. It was a hospital-based study in which 58 patients were enrolled. ASST was done in all with routine investigations including Absolute Eosinophil Count (AEC), Thyroid stimulating hormone (TSH) and Immunoglobulin E(IgE). ASST was positive in 44.8% out of 58 patients. ASST positive patients showed longer disease duration, higher severity and more generalised disease than the negative group. AEC was relatively lower, although statistically insignificant in ASST positive patients (284.21±57.43 cells/ul) as compared to AEC in ASST negative patients (310.64±71.05 cells/ul) (p=0.131). TSH on the other hand showed comparable values in both the groups (p=0.744). Mean serum IgE showed statistically significant difference between those who were ASST positive (297.96 ±42.34 IU/ml) vs ASST negative. (323.57 ±44.16 IU/ml) (p=0.029*). ASST can serve as a useful test to diagnose patients with autoimmune urticaria which can often be more severe and prolonged as well as being refractory to conventional treatment. Lower values of AEC and IgE in ASST positive patients may complement the diagnosis of autoimmune urticaria.