Objective To investigate the distribution of serum allergens in children with respiratory allergic or infectious diseases,and then provide evidence for the prevention and treatment of children's respiratory allergic and infectious diseases.Methods The clinical data of 2 334 children aged 1 to 14 years old(median 5 years)visited Shengjing Hospital Affiliated to China Medical University from April 2019 to June 2022 were retrospectively analyzed.All the children were diagnosed with respiratory allergic or infectious diseases.The Phadia 250 automatic fluorescence enzyme immunoassay system and its supporting detection reagents were used to detect serum sIgE to allergens and statistical analysis was conducted using the GraphPad Prism 8.0 software.Results The positive rates of sIgE to allergens in children with respiratory allergic diseases(n=1 151)and respiratory infectious diseases(n=1 183)were 75.85%and 47.68%,respectively.The main allergen in the children with asthma was a mixture of dust mites(44.18%),followed by a mixture of fungi(40.64%).The main allergens in the children with allergic rhinitis were a mixture of dust mites and weed pollen,both accounting for 52.51%.The common allergen of respiratory infectious diseases was mold mixture(27.81%),followed by a mixture of dust mites(24.77%).The main allergen in children under 7 years old was a mixture of fungi(33.31%).As age increased,the positive rates of allergens in different combinations increased.The positive rates of serum sIgE to dust mite mixture,dander mixture,and weed pollen mixture in children aged≥7 years old were significantly higher than those in children aged≤3 years old and 4-6 years old(P＜0.000 1).The positive rate of serum sIgE to allergens in male patients(64.33%)was significantly higher than that in female patients(56.33%,χ2=14.29,P=0.000 2).Among various disease groups,the levels of sIgE to dust mite mixture and weed pollen mixture were distributed at levels 1-6,with the highest distribution rate at level 6 in allergic rhinitis.Each disease group was associated with one allergen or a combination of two allergens.As the number of allergen combinations increased,the positive rate of sIgE gradually de-creased.The tIgE levels in children with allergic rhinitis were significantly higher than those in children with asthma,upper respiratory tract infection,and lower respiratory tract infection(all P＜0.005).Conclusion Dust mite mixture and mold mixture are common al-lergens in children with asthma,while weed pollen mixture and dust mite mixture are common allergens in children with allergic rhini-tis.As age increases,children become more and more allergic to dust mite,mold,dander,weeds,and pollen.