Abstract: Dong Dake, Yang Lijia, Pan Zhanyan Department of Dermatology, Wuxi No. 2 People′s Hospital, Wuxi 214002, Jiangsu, China （Dong DK, Yang LJ）; Department of Dermatology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200127, China （Pan ZY） Corresponding author: Pan Zhanyan, Email: paneth@msn.com 【Abstract】 Objective To investigate changes of thyroid function indices and their correlation with blood routine examination results, high-sensitivity c-reactive protein （hsCRP） levels and erythrocyte sedimentation rate （ESR） in 30 inpatients with acute urticaria. Methods Thyroid function indices were retrospectively analyzed in 30 inpatients with acute urticaria （patient group） and 30 healthy controls （control group）, including total triiodothyronine （TT3）, total thyroxine （TT4）, free triiodothyronine （FT3）, free thyroxine （FT4）, thyroid-stimulating hormone （TSH）, anti-thyroglobulin antibody （TG-Ab） and anti-thyroid peroxidase antibody （TPO-Ab）. A correlation analysis was done between thyroid function indices and blood routine examination results （white blood cell ［WBC］ count, neutrophil count, hemoglobin）, hsCRP levels and ESR. Results Abnormal thyroid function indices were observed in 23 （23/30, 76.7%） patients with acute urticaria. Compared with the control group, the patient group showed significantly decreased levels of FT3, TT3, TT4 and hemoglobin （t = 6.39, 5.55, 3.57, 3.70, all P < 0.01）, but significantly increased positive rates of thyroid autoantibodies （χ2 = 7.68, P < 0.01） as well as WBC counts, neutrophil counts, hsCRP levels and ESR （t = 3.96, 8.73, 2.51, 2.35, all P < 0.05）. There was a positive correlation between hemoglobin level and FT3, TT3, TT4 levels （r = 0.63, 0.59, 0.37, all P < 0.05）, but a negative correlation between neutrophil count and FT3, TT3, TSH levels （r = -0.45, -0.50, -0.37, all P < 0.05）, as well as between TT3 and hsCRP levels （r = -0.39, P < 0.05） in the patient group. Conclusions Patients with severe acute urticaria usually show abnormal thyroid function during attacks, which mainly manifests as low T3 syndrome and high positive rates of thyroid autoantibodies, and may be associated with decreased hemoglobin levels and infection.