[Evaluation of the relationship between immediate hypersensitivity and environmental factors by intracutaneous skin tests and specific IgE antibodies in allergic children. Part 2. The age distribution of immediate hypersensitivity by intracutaneous skin test and radioallergosorbent test].

To evaluate immediate hypersensitivity and environmental factors, 2,187 allergic children were given intradermal skin tests (ID test) and specific IgE antibodies (RAST) at Kudanzaka Hospital for 21 years (1967-1987). The incidence of positive ID test to house dust (HD) was 23% at 1 year, 50% at 2 years, 63% at 3 years and 84% at 8 years of age. The results of average positive test obtained at an earlier age in 1975 and 1985 than in 1965. Children born recently begin to have positive test scores earlier than those born between 1965 and 1969. This could be related to the recent increase in the number of HD mites. The incidence of positive ID test to Japanese cedar pollen (sugi) was 5% at 1 year, 10% at 4 years, 16% at 8 years and 30% at 15 years of age. The positive test scores were again obtained at an earlier age in 1975 and 1985 than in 1965, in the same way as for HD mites. Children born between 1965 and 1969 showed 30-60% positive rate after 13 years of age; this level was seen after 10 years of age in children born in 1975 and 1979, and after 6 years in those born between 1980-1984. This could be due to the recent increase in the amount of sugi pollen. Only Candida showed any significant rises in positive rate 27% at 1 year of age; slow increase was observed in the case of ragweed, molds, epidermals and others. No remarkable change was seen in ragweed and Alternaria at the years of examination and the years of birth.