Nationwide investigation of insect allergy in patients with allergic rhinitis

To clarify the role of insects as allergens in allergic rhinitis (AR), specific IgE antibodies (sIgE) to the moth, midge, and cockroach together with 10 other allergens were measured using sera from 560 AR patients, who visited 20 otolaryngological clinics nationwide from Hokkaido to Kyushu. Nasal challenge tests were also conducted with allergen disks of these 3 insects in 65 AR patients. Frequencies of sIgE positive to the moth, midge, and cockroach were 32.5%, 16.1%, and 13.4%. Frequencies of sIgE positive to these insects were not affected by patients' residential location, age, medication, or association with bronchial asthma. The prevalence of patients with positive nasal challenge increased depending on the RAST class to the insects. Among the patients whose RAST class were 3 and 4, nasal challenges with cockroach or moth extracts were positive in 55.6% or 61.5%. A strong correlation of sIgE titers was observed between the moth and midge, but the correlation between the cockroach and moth, and between the cockroach and midge were weak. No correlation of sIgE titers was found between house dust mites and these 3 insects. These results show that the moth, midge, and cockroach are inhalant allergens causing allergic rhinitis in Japan.