We investigated possible influence of 17 allergy-associated factors on atopic dermatitis and allergic rhinitis using Multiple factor analysis in 150 asthmatic children. Atopic dermatitis was complicated in ninety-seven cases and allergic rhinitis in ninety-seven cases. 17 allergy-associated factors were as follows: 1) sex, 2) age, 3) onset age of asthma, 4) family history of allergy, 5) peripheral eosinophil counts, 6) IgE RIST, 7) IgE RAST score to egg white, 8) IgE RAST score to milk, 9) IgE RAST score to soybean, 10) IgG4 antibody titers to egg white, 11) IgG4 antibody titers to milk, 12) IgG4 antibody titers to soybean, 13) IgE RAST score to house dust, 14) IgE RAST score to Dermatophagoides farinae, 15) severity of asthma, 16) exercise-induced asthma, 17) atopic dermatitis or allergic rhinitis. We concluded as follows: 1) Factors which more strongly influenced both atopic dermatitis and allergic rhinitis were IgE RAST score to D.f., positive family history of allergy, IgE RIST and eosinophil counts. 2) Combination with high levels of IgG4 antibody to 3 food allergens such as egg-white, milk and soybean and IgE RAST to egg-white has a strong influence on atopic dermatitis, but high levels of IgG4 antibody to 3 food allergens except high level of IgG4 antibody to soybean have a weak influence on allergic rhinitis.