Abstract: 【Abstract】 Objective To investigate clinical application of critical temperature threshold （CTT） measurement by using a temperature tester in the diagnosis of cold contact urticaria, and to explore relationships of CTTs with disease activity, disease control condition and quality of life in patients with cold contact urticaria. Methods A total of 20 patients with cold contact urticaria were collected from Department of Dermatology, Peking University First Hospital from October 2017 to March 2019. Disease activity was assessed by the patients themselves at the first visit; the CTT was measured, and dermatology life quality index （DLQI） was evaluated by the patients themselves at the first visit and subsequent 2 follow-up visits. At the second follow-up visit, disease control condition was evaluated in the patients. Spearman correlation analysis was used to analyze correlations of CTTs with disease activity, CTT improvement and disease control condition. Friedman test was used to compare the improvement of CTTs and DLQI during treatment, and Bonferroni multiple test was used for multiple comparisons. Results Based on the patients′ self-assessed disease activity, there were 3 patients with mild cold contact urticaria, 8 with moderate cold contact urticaria, and 9 with severe cold contact urticaria, and the disease activity was positively correlated with CTTs （rs = 0.573, P = 0.008）. Clinician assessment of disease control condition showed 3 patients with poor disease control, 6 with fair disease control and 9 with good disease control, and the disease control condition was positively correlated with the improvement of CTTs （rs = 0.516, P = 0.020）. The CTTs were （20.10 ± 4.67） ℃, （10.75 ± 5.30） ℃, and 5.50 （4.00, 10.75） ℃ （expressed as median ［P25, P75］） at the first visit and 2 follow-up visits respectively, and significantly differed among different visits （χ2 = 34.16, P < 0.001）; meanwhile, the DLQI scores were 19.75 ± 3.81, 8.45 ± 6.27, 0.50 （0, 9.00） （expressed as median ［P25, P75］） respectively, and there was a significant difference among different visits （χ2 = 35.23, P < 0.001）; the CTT and DLQI were significantly lower at the 2 follow-up visits than at the first visit （all P < 0.001）. Conclusion CTTs can reflect disease activity in patients with cold contact urticaria, and are correlated with the quality of life and disease control condition.

Key words: Urticaria, Cold temperature, Skin provocation tests, Severity of illness index, Critical temperature threshold