Introduction: We explored the cross-reactivity among 19 common allergen sources and evaluated the influence of serum IgE concentrations and the number of sensitized allergens on the incidence of allergic symptoms. Methods: We conducted this cross-sectional analysis using data from the National Health and Nutrition Examination Survey (NHANES) 2005-2006 which is a program of studies designed to assess the health and nutritional status of adults and children in the USA. After excluding participants with missing data from the allergen IgE test, allergy questionnaire, and respiratory health questionnaire, a total of 7,224 participants aged 6 years and older were included, as children younger than 6 years old did not complete all 19 allergen-specific IgE tests. Spearman correlation analysis was used to analyze the cross-reactivity between allergen sources. An independent sample Kruskal-Wallis test was performed to investigate the relationship between the serum-specific IgE levels of 19 allergens and the incidence of allergic symptoms. Results: The cross-reactivity between D. farinae and D. pteronyssinus was the strongest (rho = 0.88), and cross-reactivity of cross-species was universal. With the increase in serum-specific IgE levels of D. farinae, D. pteronyssinus, oak, and birch, the incidence of sneezing increased (p < 0.05). With the increase in serum-specific IgE levels of cats, dogs, peanuts, Aspergillus, and Alternaria, the incidence of wheezing increased (p < 0.05). The incidence of rash was positively correlated with serum-specific IgE levels of D. farinae, D. pteronyssinus, shrimp, and peanut (p < 0.05). The incidence of wheezing continued to increase with an increase in sensitized allergens. When participants were sensitized to <10 allergens, the incidence of sneezing continued to increase as the number of sensitized allergens increased, whereas the incidence of rash did not have a clear association with the number of sensitized allergens. Conclusion: Species that are biologically close are more likely to have antigen cross-reactivity, while cross-reactivity among different species is common. Different allergens tend to cause different allergic symptoms. Different allergic sites in the body have inconsistent responses to the number of sensitized allergens.