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Background: In 2012, we clarified that the prevalence of food-dependent exercise-induced anaphylaxis (FDEIA) was 0.018% in junior-high students in Yokohama, Japan. Furthermore, although different from FDEIA, one student who had completed oral immunotherapy developed anaphylaxis during exercise after eating causative food. There have been few large-scale epidemiological studies of FDEIA, however, in elementary school children, therefore we conducted an epidemiological study in elementary school children in Yokohama to clarify the frequency and characteristic of FDEIA., Methods: We sent a questionnaire regarding the occurrence of FDEIA to all 348 public elementary school nurses in Yokohama. We also compared the results with those for junior-high school that we previously reported. We excluded those children with a past history of immediate food allergy who had achieved desensitization status after oral immunotherapy, from FDEIA, and instead defined them as having desensitization status and exercise-induced anaphylaxis (DEIA)., Results: Of 348 school nurses, 317 responded (91.1%). Overall, eight of 170 146 children were diagnosed with FDEIA, which was significantly lower than the prevalence in junior-high school students (0.0047% vs 0.018%, P = 0.0009). The causative foods were wheat (n = 4), and soy, fruit, crustaceans, and squid (n = 1 each). Four children had DEIA and the causative foods were wheat and milk (n = 2 each). Multiple episodes occurred in five children with FDEIA and in three children with DEIA., Conclusions: FDEIA was far less common in elementary school than in junior-high school, and wheat was the major causative food. The new appearance of DEIA was notable. Decreasing episode recurrence remains an issue that needs to be resolved., (© 2018 Japan Pediatric Society.)

Food-dependent exercise-induced anaphylaxis (FEIAn) is a rare disease. The disease is classified into physical allergy and/or a subtype of food allergy. However, the pathophysiology and epidemiology are not well known. In this article we presented our studies of the epidemiology of FEIAn, in school students (elementary. junior-high, and high school) in Yokohama City and/or Kanagawa Prefecture, Japan. Also, we reviewed FEIAn cases in the literatures in Japan as well as in foreign countries. Six hundred and seven school nurses responded the questionnaire, 30 (Male:Female, 24:6) cases of FEIAn and 44 (M:F, 22:22) with exercise-induced anaphylaxis (EIAn) among 353977 students were reported. The frequency of FEIAn and EIAn was 0.0085% and 0.012%, respectively. Only one third of nurses had knowledge of FEIAn. We performed provocation tests in 11 of the 30 students with FEIAn and confirmed the diagnosis. We demonstrated transient increases in plasma histamine but not serum tryptase levels during the tests. The causative foods were mainly wheat and crustaceans in 170 Japanese cases and beans and wheat in foreign countries. As for exercise, ball games and running were more frequent sports in both groups. The age of first episode of FEIAn was 10 to 20 years old in most cases. Provocation test often fails to induce symptoms. In addition, we do not have the standard method. Now we are establishing the protocol. FEIAn and EIAn are relatively rare among school students in Japan. There is no evidence to prevent the onset of FEIAn with medicines. Therefore, to avoid serious outcomes and unnecessary restriction, we believe it is important to be familiar with the diseases for not only physicians, but also school nurses and teachers of physical education.

Background: Anaphylaxis is one of the severest forms of allergic diseases. Some kinds of mushroom are known as causative allergens in food anaphylaxis. Matsutake mushroom (Tricholoma matsutake) is a typical edible mushroom available in autumn in Japan. We encountered an 8-year-old Japanese girl who developed anaphylaxis after ingesting matsutake mushrooms., Methods: We studied the case in detail, by measuring specific IgE antibodies and conducting skin tests, to confirm the diagnosis. We also detected seven cytokines and chemical mediators in the blood in order to study the pathophysiology of the anaphylaxis., Results: We diagnosed anaphylaxis caused by ingestion of matsutake mushrooms based on the following. A skin prick test showed a positive reaction to matsutake mushroom, and specific IgE antibody for matsutake mushroom extract was detected in the patient's serum by fluorometric ELISA. Blood levels of chemical mediators including histamine, ECP, tryptase and cytokines such as IL-6, IL-5 and IL-10 but not IFN-gamma also increased significantly during the allergic episode., Conclusions: We demonstrated that chemical mediators including histamine, tryptase and ECP as well as several cytokines were involved significantly during the episode of anaphylaxis. In addition, eosinophils as well as mast cells played significant roles in the anaphylaxis. Furthermore, CD4+CD25+ T regulatory cells that released IL-10 were likely activated during the anaphylaxis. Matsutake mushroom should be considered as a causative allergen in food anaphylaxis.