Title : Assessment of autologous serum skin test and efficacy of autologous serum therapy in chronic urticaria
Abstract:
Background: Chronic urticaria is a common distressing dermatoses which affects the patient’s quality of life to a great extent, causing restrictions in daily life activities and social life, due to unrelenting symptoms and reduced dermatology life quality index(DLQI). Treatment of chronic urticaria remains unsatisfactory with long term requirement of medications having potential side effects. Autologous serum skin test(ASST) is a useful diagnostic aid in identifying chronic autoimmune urticaria with a sensitivity of approximately 70 % and specificity of 80%. Autologous serum therapy(AST) is potentially curative modality in patients with chronic urticaria.
Aims and Objectives: The aim is to assess the autologous serum skin test in chronic urticaria and to evaluate the efficacy of autologous serum therapy in chronic urticaria.
Materials and Methods: A prospective, non-randomized uncontrolled study of 50 patients with chronic urticaria was conducted in a tertiary care center attached to a medical college over a duration of one year, after obtaining approval from institutional ethics committee. After receiving written informed consent from participants, ASST was performed in all the patients followed by 8 weekly intramuscular injections of autologous serum. Under aseptic precautions, 2ml of patient’s venous blood was taken from antecubital vein, collected in a sterile glass tube and allowed to clot for 30 minutes at room temperature. The serum was then separated by centrifugation at 2000 rpm for 15 minutes. Approximately 0.05 ml of autologous serum was injected intradermally over flexor aspect of left forearm. Equal amount of normal saline (negative control) was injected intradermally over flexor aspect of right forearm. Results were read after 30 minutes. The test was considered positive if wheal and flare occurred over the serum injection site with a diameter of at least 1.5 mm or more than that of saline-induced response. Every week for eight consecutive weeks, 5 ml blood was drawn, serum separated and 0.05 ml/kg body weight of patients serum was injected deep intramuscularly in alternate upper outer quadrant of the gluteal region.
Results: Out of the 50 patients with chronic urticaria, 60%(30) patients were ASST positive of which 19 were females and 11 were males; whereas 40%(20) were ASST negative of which 13 were females and 7 were males. Significantly higher proportion of ASST(+) patients were classified as severe as compared to the ASST(-) patients at baseline and it was statistically significant(66.7 vs. 45%;p = 0.01). At the final follow up visit (12th week), 35.7 %(10) patients were completely clear, 32.1%(9) had only mild diseases in the ASST positive patients whereas in the ASST negative patients 23.5%(4) were completely clear and 29.4%(5) had mild improvement. Among ASST positive patients, 35.7%(10) showed complete remission and 32.1%(9) showed marked improvement whereas in ASST negative patients 23.5%(4) showed complete remission and 29.4%(5) showed marked improvement. These observations were found to be statistically significant (p value 0.02). Five(10%) patients were lost to follow up.
Conclusion: Autologous serum therapy was found to be safe, simple, well-tolerated and cost-effective in significant proportion of ASST positive patients with chronic urticaria.
Audience Take Away Notes:
Treatment of chronic urticaria remains unsatisfactory with long term requirement of medications having potential side effects. Autologous serum skin test (ASST) is a useful diagnostic aid in identifying chronic autoimmune urticaria with a sensitivity of approximately 70 % and specificity of 80%. Autologous serum therapy (AST) is a safe, simple, well-tolerated and cost-effective in significant proportion of ASST positive patients with chronic urticaria.
