[Nationwide intradermal test with chironomid midge extract in asthmatic children in Japan].

Chironomidea (Insecta) is recently considered one of the most common inhalant antigen in Japan. Intradermal tests with Chironomus plumosus (CP) extract were undertaken on seven hundred and eighteen asthmatic children aged from 6 to 15 years in 10 areas (11 medical institutions) in Japan. The number of cases who showed positive intradermal tests with CP extract was 200 (27.9%) and the positive rate increased in proportion to their age (p less than 0.005). In each of the 11 medical institutions the positive rates ranged from 12.6% in Akita to 45.5% in Okinawa. There were no significant correlations between the results of the intradermal test with CP and those of RAST, prick test and intradermal test with mite, HD and silk, whereas correlation was noted in the prick test with silk (p less than 0.01). The CP positive asthmatics had significantly more attacks than the CP negative ones in the summer (p less than 0.01). The positive rate of asthmatics living near paddy or farm fields was significantly higher than that of those in urban residential areas (31.3% vs 23.8%, p less than 0.05). Chironomid midge is one of the most common and important allergen in Japan.