Publication:

Autologous serum skin test in 250 patients of chronic spontaneous urticaria at tertiary care hospital in Gujarat

Background Chronic urticaria (CU) is defined as urticaria persisting daily as or almost daily for more than 6 weeks and affecting 0.1% of the population. In chronic autoimmune urticaria, immunoglobulin G (lgG) auto antibodies react to the alpha subunit of the high-affinity lgE receptor (FceR1) on dermal mast cells and basophils, leading to chronic stimulation of these cells. This results in the release of histamine and other inflammatory mediators which cause urticaria and angioedema. More than half of the patients have autoimmune urticaria. ASST is the only in vivo test to detect autoimmune urticaria. The aim was to study the frequency of ASST positivity among patients with chronic spontaneous urticaria and to identify the clinical and laboratory parameters associated with positive ASST.

Methods The present study is prospective observational study of chronic spontaneous urticaria. ASST was performed in 250 patients fulfilling exclusion and inclusion criteria. Baseline investigations (CBC, ESR, urine, stool, RBS and CRP) were done for all the patients whereas specific investigations (ANA, Thyroid Profile, IgE, Anti H.Pylori IgG and skin biopsy) were done in selected cases.

Results Out of 250 patients examined, 60% had positive autologous serum skin test suggestive of autoimmune urticaria. H. pylori antibodies were significantly higher (29%) in ASST positive patients. While antinuclear antibody (ANA) was positive in 4% and thyroid antibodies were present in 7% of patients with positive ASST. Serum IgE was elevated in 32% ASST positive patients.

Conclusions ASST is an easy, simple and cost effective screening test for chronic autoimmune urticaria.