Exercise-induced hives
During exercise, your body releases histamines, which can trigger an allergic response that causes rashes and hives. This reaction is similar to an allergic reaction to dust or pollen, and the rashes usually go away within 30–60 minutes after you cool down. However, some people may be sensitive to histamines and experience more prolonged or painful rashes, along with other symptoms like headaches, diarrhea, or shortness of breath. To help with exercise-induced hives, you can try taking an antihistamine like Zyrtec, Benadryl, or Allegra. Your dermatologist can also recommend other treatments.
?https://www.mayoclinicproceedings.org/article/S0025-6196%2811%2963475-7/fulltext
有點意思。文中建議運動前四小時不要吃東西
