Abstract: Objective To determine whether there are differences of clinical features or severity of chronic idiopathic urticaria(CIU) between patien ts with positive(ASST+)and negative (ASST-)autologous serum skin test. Methods The clinical features of the patients with ASST+ were evaluated and compared with those of the patients with ASST-.Anti-thyroid antibodies in serum were det ected by radioimmunoassay. Results There were no significant difference of age distribution and course of the disease between the ASST+ and ASST-urticaria patients(both P>0.05).ASST+ patients had larger wheals(P<0.05),more wheals(P<0.01),longer periods of individual wheals(P<0.05),higheritch scores(P<0.01),more systemic symptoms(P<0.01)and higher positive rate of anti-thyroi d antibodies than ASST-patients did.ASST+ patients also had the history of autoimmune conditions more often than ASST-patients did(P<0.05). Conclusion The positive autologous serum skin test indicates a subset of patients with much severe CIU.

Key words: Urticaria, Intradermal tests, Autoimmune diseases