Regional differences in the prevalence of oral allergy syndrome among Japanese children: A questionnaire-based survey

Abstract

Background: Oral allergy syndrome (OAS) is characterized by an immediate allergic reaction that mainly or partially affects the oral mucosa, pharynx, or lips, and it is usually caused by ingesting fresh fruits or vegetables. Most patients with OAS also have allergic rhinitis due to pollen. As allergic rhinitis is increasingly prevalent in the Japanese population and the age at disease development is decreasing, morbidity associated with OAS among the younger population is likely to increase. However, there is little information about the prevalence of this disease among Japanese children, specifically the influences of residency in regions with different environments. Objectives: To investigate the prevalence of OAS and seasonal allergic rhinitis (SAR) among Japanese children and evaluate the relationship between OAS and SAR. Methods: We administered a questionnaire-based survey among children aged 7–15 years, living in 4 cities in central Japan. Results: The questionnaires were administered to 4103 children and completed by 3365 (82.0%). Overall, 524 children (15.6%) reported OAS-like symptoms after ingesting fruits or vegetables. The prevalence of seasonal SAR and oral symptoms significantly differed among the 4 cities. The total prevalence of oral symptoms co-occurring with SAR was 24.4%, which was significantly higher than the prevalence of symptoms occurring without SAR (10.2%, p < 0.001). Conclusion: Herein, oral symptoms were more likely to occur in patients with SAR than in those without SAR. The prevalence of SAR and food-induced oral symptoms significantly differed among the regions, suggesting they might be affected by regional differences in lifestyles and flora.