Exercise can trigger allergic reactions

Forty years ago, three American scientists reported symptoms triggered by physical exertion for the first time. The symptoms were observed in a 31-year-old long-distance runner. If he ate crustaceans such as shrimp before his workout, a skin rash and severe itching would occur. The symptoms became worse with every attack. Finally, he experienced such severe swelling of the mucous membranes that he was barely able to breath and required emergency treatment. The strange thing was that if the athlete refrained from exercising after eating shellfish, he tolerated the meal without any problems. Pulmonologist Robert Maulitz from the University Hospital in Denver, Colorado, and his colleagues called the phenomenon exercise-induced anaphylaxis (EIA).¹

Checking the facts

“Exercise-induced anaphylaxis with and without food as a trigger is rare, but can be life threatening”, said Wojciech Barg, an internal medicine and allergy specialist at Wrocław Medical University. What exactly happens is still unclear, added Barg.² Nonetheless, detailed findings are already available.^2,3

One in ten anaphylactic reaction occurs together with exercise.
EIA typically occurs for the first time between ten and 30 years of age. But children as young as three and adults over 75 have also been diagnosed with EIA.
Women appear to be twice as likely to experience EIA as men.
It is estimated that a third or even half of all cases of EIA are related to food that was previously ingested. The main triggers are tomatoes, nuts, shellfish, and grain products (cereals).
Other EIA triggers include high or low temperatures, hormonal changes during the menstrual cycle, dental amalgam fillings, and certain painkillers such as acetylsalicylic acid (e.g. Aspirin^®, Acesal^®, Thomapyrin^®), diclofenac or ibuprofen.
Any type of physical exertion can trigger EIA. The risk is usually higher with jogging, tennis, dancing, cycling or other strength and endurance sports than after a walk or light gardening work.

Recognise and prevent symptoms

The initial symptoms can usually be felt as soon as half an hour after starting the exercise. A hoarse voice, skin rash with blisters and itching (urticaria), abdominal cramps, diarrhoea, circulatory problems and acute respiratory distress can all be signs of EIA.

“Prevention is the best way to manage exercise-induced anaphylaxis”, says Peter Huynh of the Kaiser Permanente Panorama City Medical Center in California.⁴ If allergic reactions occur during exercise, advises the allergy specialist, exercise should be discontinued immediately. If breathing or circulatory problems occur, bystanders should be asked for assistance and to call emergency medical services.

Despite the risk, people who have already experienced EIA can still exercise as long as they are adequately informed about how to prevent symptoms and manage life-threatening reactions. For example, if EIA is caused by certain foods, these should not be eaten for at least four hours before exercising. Symptoms can be treated with an allergy emergency kit containing an antihistamine, an adrenaline autoinjector and cortisone drugs while waiting for emergency medical services to arrive.