Background: Chronic urticaria is a distressing condition which affects the quality of life of patients. Majority of chronic urticaria patients have no external cause and termed as chronic idiopathic urticaria. Approximately 30-40% of patients with chronic idiopathic urticaria have autoimmune urticaria. Asst is a simple inexpensive test which helps to classify chronic urticaria into idiopathic urticaria and autoimmune urticaria. Aims: To identify autoimmune urticaria amongst the chronic idiopathic urticaria. Methods: A total of 100 cases of chronic urticaria, attending the skin opd from march to February were taken up for the study. After a detailed clinical history and examination laboratory investigations like Complete haemogram, Blood sugars, Erythrocyte Sedimentation Rate (ESR), Absolute eosinophil count (AEC) was sent for all the patients. ASST was done. A positive test was defined as a serum-induced wheal response with a diameter of 1.5 mm or more than the saline induced response at 30 minutes. Results: Of all the patients studied 41% of the patients showed a positive reaction. Most of whom were females and in the age group of 21-30 years. The mean urticaria activity score was 5.11 in the ASST positive patients compared to 4.39 in the ASST negative group. In the ASST positive group, 80.48% had daily occurrence of lesions while 62.71% of the asst negative group got lesions daily. Patients with positive ASST had larger extent of body involvement. Conclusion: We concluded that autoimmune urticaria has greater frequency and larger extent and higher urticarial activity score than other types of urticaria.

Keywords: Chronic urticaria; ASST; Autoimmune urticaria.