Sensitization to insects in urban or rural area, and their clinical and immunological features

Background: Prevalence of sensitization to insects and its clinical and immunological features remains largely unclear in Japan. Patients and methods: The study includes 524 patients (316 from International University of Health and Welfare (IUHW) Mita Hospital in Tokyo and 208 from IUHW Hospital in Tochigi) who complained of nasal symptoms and underwent ImmunoCAP IgE tests. We compared the ratio of insect sensitization (moth, chironomid and cockroach) in Tokyo and Tochigi and investigated the clinical and immunological features of the patients, focusing particularly on those with sensitization to insects alone. Results: The ratio of sensitization to moth, chironomid and cockroach were 30.7%, 10.0% and 10.6% in Tokyo, and 26.4%, 10.6% and 12.5% in Tochigi, respectively. The geographical comparison showed no significant difference. Among the insect allergic patients, 95.1% were sensitized to the moth. In comparison to those insensitive to arthropods, the group of patients sensitized to insects was male dominant and indicated higher total IgE. The group of those sensitized only to insects was relatively older than that of those sensitive to not only insects but also other inhaled allergens. Conclusion: The study showed the high ratio of sensitization to the moth carried significance of the moth as an allergen in allergic rhinitis. The ratio of insect sensitization showed no significant different between urban and rural area. Patients sensitized to insects alone were dominated by elderly male with high total IgE.