Food-dependent exercise-induced anaphylaxis occurred only in a warm but not in a cold environment.

Food-dependent exercise-induced anaphylaxis (FDEIA) is a type of exercise-induced anaphylaxis associated with postprandial exercise. We describe a 19-year-old man with FDEIA. Our patient complained of urticaria, angioedema, dizziness and hypotension associated with exercise after ingestion of walnut-containing foods in a warm environment. Skin prick test and prick to prick test were positive for walnut antigen. The attack didn't occur by free running outside for 10 min 2 h after taking walnuts, and the temperature was about -2℃. Food-exercise test was done again in a warm environment based on prior history. Anaphylaxis was developed after exercise for 10 min in a warm environment after taking walnuts. Some environmental factors such as high temperature and high humidity or cold temperature may influence exercise-induced anaphylaxis. In our case, the cofactor was a warm environment: the challenge test done in a cold environment was negative, but positive in a warm environment. Physicians should be aware that the challenge test of FDEIA can show different results depending on temperature.