[A case of food-dependent exercise-induced anaphylaxis caused by ingestion of orange]

The patient was a 10-year-old girl who presented with a history of anaphylactic episodes on three occasions, that developed in association with exercise after she ate citrus fruit. She underwent tolerance tests, as food-dependent exercise-induced anaphylaxis (FDEIA) induced by citrus fruit was suspected. The result of the test for the combination of intake of oranges and exercise was negative. The patient presented with swollen eyelid and wheezing following combined intake of orange and aspirin, based on which she was diagnosed as having FDEIA. Many patients developing an allergic reaction to fruit are diagnosed as having oral allergy syndrome (OAS), and only few cases of FDEIA are reported. Immunoblot tests revealed antigens of 9 kDa, 39 kDa and 53 kDa in this patient, and an inhibition study with oranges revealed that the 39 kDa and 53 kDa antigens were probably antigen-specific allergens. Although the studied patient showed a strongly positive result for IgE antibodies specifically directed at cedar pollen, no common antigenicity with cedar pollen could be recognized. The final diagnosis was a type of FDEIA caused by 39 kDa and 53 kDa proteins, which are different from antigens previously identified in patients with citrus fruits allergy. It should be the first report of such a case.