Comparison of sensitization and prevalence of Japanese cedar pollen and mite-induced perennial allergic rhinitis between 2006 and 2016 in hospital workers in Japan.

BACKGROUND: The prevalence of allergic rhinitis (AR) is increasing worldwide, mainly due to an increase in antigen exposure. We conducted an epidemiological study involving the staff of the University of Fukui Hospital and its associated hospital in 2006. There were 1540 participants aged ≥20 years, and the rates of Japanese cedar (JC) pollinosis and mite-induced perennial allergic rhinitis (PAR) were 36.8% and 15.8%, respectively. In 2016, we conducted a second survey. METHODS: The rate of sensitization to JC pollen and mites and the prevalence of JC pollinosis and mite-induced PAR were analyzed based on data from questionnaires and antigen-specific immunoglobulin E (IgE) levels. RESULTS: In the present study, we analyzed data of 1472 participants aged between 20 and 59 years. Total sensitization to JC pollen and total prevalence of JC pollinosis were 57.8% (851/1472) and 40.8% (601/1472), respectively. Total sensitization to mites and total prevalence of mite-induced PAR were 41.4% (610/1472) and 18.8% (276/1472), respectively. Total prevalence of JC pollinosis and mite-induced PAR increased significantly over a decade. Among the 334 people who participated in the 2006 and 2016 cross-sectional studies, 13% of JC pollinosis and 36% of mite-induced PAR experienced remission. However, since the number of new onset cases was higher that the number of remission cases, a slight increase in prevalence was observed over a decade. CONCLUSIONS: The prevalence of JC pollinosis and mite-induced PAR continues to show increasing trends, accompanied by an increase in antigen exposure. The remission rate of JC pollinosis was particularly low.

Epidemiological study of oral allergy syndrome in birch pollen dispersal-free regions.

BACKGROUND: Oral allergy syndrome (OAS) is an immediate allergy caused by a cross-reaction of highly homologous common antigens (pan-allergens) contained in fruits/vegetables and pollen. METHODS: A questionnaire was provided to 6824 outpatient visitors and serum levels of specific IgEs against crude antigens and pan-allergen components were measured to study the relationship between the prevalence of OAS and pollinosis in the Fukui Prefecture where there is almost no dispersal of birch pollen. RESULTS: The prevalence of OAS was 10.8%. The rate of pollinosis complication in the OAS group was 67.4%, and OAS was observed in 16.8% of pollinosis patients. Causative foods in order of frequency were melon, pineapple, kiwi fruit, peach, and apple. A significantly higher number of patients from the OAS group were positive for birch, alder, and timothy grass-specific IgE. The rate of positivity for anti-component IgE corresponding to pollen in OAS group was also significantly higher. Of 34 patients with OAS caused by eating apples, 28 (82.4%) were positive for Mal d1-specific IgE. Of the 52 patients with peach-induced OAS, 41 (78.8%) were positive for Pur p1-specific IgE. The concordance rates between crude antigen-specific IgE and anti-PR-10 component-specific IgE were 87.1% and 93.3% for apple and peach respectively. CONCLUSIONS: In regions where birch pollen is not dispersed, OAS patients have a significant association with the onset of Bet v1-associated allergy. Anti-PR-10 component IgE was useful in diagnosing OAS, and crude antigen-specific IgE was also associated with apple and peach allergies.