Food-dependent exercise-induced anaphylaxis diagnosed based on a increased plasma concentration of histamine without developing any symptoms

Abstract

We report the case of a 15-year-old boy who developed anaphylactic symptoms including facial reddening and swelling and dyspnoea during running after taking ramen noodles. We suspected food dependent exercise-induced anaphylaxis (FDEIA) and performed challenge tests as he had no history of acute allergic reaction to wheat. Symptoms were not elicited with any of the three combination challenge tests ; wheat noodles and exercise, premedication of aspirin and wheat noodles, and premedication of aspirin, wheat noodles and exercise. However, plasma histamine concentration increased after each of the three tests ; 200%, 190% and 248% of each of pre-test values were obtained, respectively. A diagnosis of FDEIA was thus made. He was prescribed an epinephrine auto-injector, instructed not to exercise during two hours after wheat intake, and told to avoid taking wheat products and exercise after he takes aspirin. Incorporation of increase in the plasma histamine concentration in diagnosis of FDEIA is very clinically important to circumvent a possible false negative in the absence of symptoms with the challenge tests.