Joe O’Leary went to dinner with his parents at around 8 p.m. one Wednesday in March of 2015. He split a pizza, topped with tomatoes and peppers, with his mom. Then he set out for the gym and hopped on the elliptical. But about a half-hour into the workout, he started feeling weird. “My eyes were watering, I was having trouble breathing,” he says. “In another five minutes I was struggling to breathe. I looked behind me into the mirror, and my eyes were swollen — every part of my face was swollen.”
O’Leary was rushed to the emergency room and pumped full of steroids and antihistamines. He’d had an allergic reaction, but not just to what he’d eaten for dinner: it was the combination of food and exercise that did him in. Doctors quickly diagnosed him with a condition called exercise-induced anaphylaxis, where a reaction to an allergen only happens in conjunction with exercise. If he combines them with exercise, O’Leary will have an anaphylactic reaction to tomatoes, peppers, soy and nuts.
Exercise-induced anaphylaxis was first described in 1979, and probably affects around 50 in every 100,000 people. While awareness of the condition among allergists has gone up, researchers and doctors still don’t know exactly why it occurs, says Maria Castells, an allergist at Brigham and Women’s Hospital.
For between 30 to 50 percent of people, the reaction comes from combining certain types of food and exercise. For others, strenuous activity triggers a reaction to drugs like aspirin. Some women only experience the phenomenon when they’re at the point in their menstrual cycle with high levels of the hormone estrogen, because it can bind to the cells involved with an allergic reaction. “