Abstract:

Fu Yuping, Li Dongning, Wang Lan, Sun Jian, Yan Tiefu, Wang Lili, Du Hongyang Department of Dermatology, First Affiliated Hospital of Liaoning Medical University, Jinzhou 121001, Liaoning, China （Fu YP, Li DN, Sun J, Yan TF, Wang LL, Du HY）; Department of Dermatology, The Central Hospital of Xiaogan, Xiaogan 432000, Hubei, China （Wang L） Corresponding author: Li Dongning, Email: ldn000123@sina.com 【Abstract】 Objective To analyze results of atopy patch test （APT） with dust mite allergens at different concentrations in patients with atopic dermatitis （AD）, and to evaluate the diagnostic value of APT. Methods Totally, 85 patients with AD were enrolled into this study. All the patients underwent APT with 5 concentrations （3 000, 5 000, 7 000, 10 000 and 12 000 pnu/g） of dust mite allergens, as well as skin prick test （SPT） with dust mite allergens. Dust mite allergens were obtained from two different manufacturers （group 1 and 2）. Enzyme-linked immunosorbent assay （ELISA） was performed to detect allergen-specific immunoglobulin E （SIgE） in sera from these patients. The sensitivity, specificity and positive predictive value of APT, SPT and SIgE assay were compared, and the results of APT were compared among different concentrations of allergens and between allergens from different manufacturers. Results When SIgE assay served as the gold standard, the sensitivity, specificity and positive predictive value in the diagnosis of dust mite allergy were 79.41%, 76.12%, and 64.29% respectively for APT, 73.53%, 80.95% and 67.57% respectively for SPT with group 1 dust mite allergens, and 81.53%, 77.78% and 65.09% respectively for APT, 76.02%, 79.85% and 66.07% respectively for SPT with group 2 allergens. When SPT was regarded as the gold standard, the sensitivity, specificity and positive predictive value in the diagnosis of dust mite allergy were 78.38%, 77.42%, 67.44% respectively for APT, 67.57%, 84.21%, 73.53% respectively for SIgE assay with group 1 dust mite allergens, 79.25%, 80.63% and 69.55% respectively for APT, 61.07%, 82.54% and 77.21% respectively for SIgE assay with group 2 allergens. There were no significant differences in the sensitivity, specificity or positive predictive value of APT or SPT between the two groups of allergens. The positive rate of APT was 8.24%, 22.35%, 29.41%, 44.71% and 41.18% respectively with group 1 allergens at 3 000, 5 000, 7 000, 10 000 and 12 000 pnu/g, and 3.53%, 23.53%, 31.76%, 34.12% and 35.29% respectively with group 2 allergens. No significant differences were observed in the positive rate of APT between group 1 and 2 allergens at same concentrations （all P > 0.05）, but a significant difference was observed in that between different concentrations of group 1 or 2 allergens （both P < 0.05）. The positive rate of APT increased with the increase of allergen concentrations, but stopped rising when the concentrations of group 1 and 2 allergens reached 7 000 pnu/g and 5 000 pnu/g respectively. Conclusions The sensitivity of APT is relatively high for the diagnosis of dust mite allergy. The positive rate of APT increased with the increase in allergen concentrations, but stopped rising when the concentrations reached a certain level.