Autologous serum skin test in chronic idiopathic urticaria.

BACKGROUND AND AIMS: Chronic urticaria has a spectrum of clinical presentations and causes. About 25%-45% of patients have histamine releasing autoantibodies in their blood. The term autoimmune urticaria is increasingly being accepted for this subgroup of patients. The term autoimmune urticaria is used to reflect advances in knowledge about functional autoantibodies that activate mast cells and basophils through cross linking high affinity IgE receptors to secrete histamine. This study was started to find out incidence of autoimmune urticaria in Indian patients. METHODS: The autologous serum skin test was done in 45 patients with chronic urticaria of more than six weeks duration. Physical urticaria patients were not included in the study. RESULTS: Twelve patients had positive autologous serum skin test suggestive of autoimmune urticaria. CONCLUSIONS: Positive autologous serum skin test was seen in 26.67% of patients which is less than reports from Western literature. This is a useful screening test for autoimmune urticaria.