Objective ·To explore the correlation between serum 25-hydroxyvitamin D [25(OH)D] levels and serum allergens in children with atopic dermatitis (AD), and provide a theoretical basis for the prevention and treatment of AD. Methods ·From November 2017 to February 2019, a total of 165 pediatric patients with AD who visited the Dermatology Department of Shanghai Children′s Medical Center were enrolled in this study. AD severity was assessed according to the severity scoring of atopic dermatitis (SCORAD). Serum total IgE and specific IgE (sIgE) levels of 19 common allergens were detected, and serum25(OH)D was determined by liquid chromatography-tandem mass spectrometry. All data were statistically analyzed. Correlation analysis was conducted by spearman's or point-biserial correlation analysis. Chi-square test was used for comparison of count data between groups. Binary linear regression analysis was used to identify the risk factors. Results ·SCORAD score was shown to be positively correlated with serum total IgE level, absolute value and percentage of eosinophils in children with AD (r=0.213, P=0.009; r=0.268, P=0.001; and r=0.249, P=0.003, respectively). However, there was no significant correlation between serum 25(OH)D concentrations and SCORAD score in children with AD, while there was a significant negative correlation between the serum 25(OH)D concentrations and the total IgE levels, and the percentage of eosinophils in children with AD (r=-0.212, P=0.011; and r=-0.174, P=0.039, respectively) was shown. In this study, the most common allergens with sIgE grade Ⅲ or above were house dust mite, egg white and cashew nut, followed by crab, cat dander, mixed mold, shrimp, dog dander, house dust and mixed tree pollen from high to low. There was no significant correlation between the number of allergen-positive items and serum 25(OH)D concentrations in children with AD (χ²=6.27, P=0.804). However, AD patients with positive house dust mite and mixed mold were statistically significant in different serum [25(OH)D] groups (P=0.000, and P=0.043, respectively). In addition, univariate logistic regression analysis showed that serum [25(OH)D] levels were risk factor for house dust mite allergy in children with AD. The risk of household dust mite allergy in children with serum 25(OH)D deficiency was 8.196 times than that of children with sufficient serum 25(OH)D (OR=8.196, P=0.000). However, serum [25(OH)D] levels were not the risk factor for house dust mite allergy in children with AD. Conclusion ·Serum [25(OH)D] levels might affect the sensitization of children with AD to house dust mite. Avoidance of allergens according to the sIgE test and Vitamin D supplementation might be of great significance in the prevention and treatment of AD.