Diagnostic value of autologous serum skin test in chronic auto immune urticaria
Keywords:Chronic urticaria, Autoimmune urticaria, Autologous serum skin test
Background: Urticaria affects up to 20% of the population during their life time. Urticaria occurring on almost all days for more than 6 weeks is classified as chronic urticaria. Chronic urticaria is one of the most vexing management problems the dermatologists face. Chronic urticaria cases in which no etiology can be found are labelled chronic idiopathic urticarial (CIU). In most cases of idiopathic urticaria, autoimmunity may be the initiating factor- chronic autoimmune urticaria. Autologous serum skin test (ASST) is a simple and reliable method to detect autoimmune urticaria.
Methods: Among patients with chronic idiopathic urticaria, ASST is done to detect ASST positivity and thereby chronic autoimmune urticaria. Patient’s serum is separated and 0.05 ml injected intradermally on left forearm. Normal saline is injected intradermally at least 5 cm away as control. Wheal and flare at serum site which is 1.5 mm more than that of control is taken as positive. Results were analyzed using Microsoft excel and Epi info7.
Results: 49 patients were studied and 34 (69.4%) showed ASST positivity, which is an indicator of autoimmune urticaria. Moreover, it was seen that ASST positive patients had more episodes of urticaria per week, compared to ASST negative patients.
Conclusions: ASST is a simple and reliable method to detect chronic autoimmune urticaria. ASST positive patients have more episodes of urticaria compared to ASST negative patients.
Saini SS. Chronic spontaneous urticaria: Etiology and Pathogenesis. Immunol Allergy Clin N Am. 2014;34:33-52.
Grattan CE, Sabroe RA, Greaves MW. Chronic urticaria. J Am Acad Dermatol. 2002;46:645-57.
Godse KV. Autologous Serum Skin Test in chronic idiopathic urticaria. Indian J Dermatol Venereol Leprol. 2004;70:283-4.
Krupashankar DS, Shashikala K, Madala R. Clinical and investigative assessment of patients with positive versus negative autologous serum skin test: A study of 80 south Indian patients. Indian J Dermatol. 2012;57:434-8.
Vohra S, Sharma NL, Mahajan VK, Shankar V. Clinico epidemiologic features of chronic urticaria in patients having positive versus negative autologous serum skin test: A study of 100 Indian patients. Indian J Dermatol Venereol Leprol. 2011;77:156-9.
Bakos N, Hillander M. Comparison of chronic autoimmune urticaria with chronic idiopathic urticaria. Int J Dermatol. 2003;42: 613-5.
Colgecen E, Ozyurt K, Gul AI, Utas S. Evaluation of etiological factors in patients with chronic urticaria. Acta Dermatovenereol Croat. 2015;23:36-42.
Yadav S, Kanwar AJ, Prasad D, Minz RW. Chronic idiopathic urticaria and thyroid autoimmunity: Perplexing association. Indian J Dermatol. 2013;58:325-7.
Sabroe RA, Seed PT, Francis DM, Barr RM, Black AK, Greaves MW. Chronic idiopathic urticaria: Comparison of the clinical features of patients with and without anti Fc ep-silon RI or anti IgE auto antibodies. J Am Acad Dermatol. 1999;40:443-50.