What Is Anaphylaxis? How Can a Person Be Allergic To Exercise?

For some people, exercise has become part of their daily routine. In rare cases, however, a person can start wheezing, itching, and breaking out in hives while exercising. Those who suffer from this condition might be experiencing a rare disorder known as exercise-induced anaphylaxis.

What Causes Allergy?

Allergies occur when a person's immune system reacts to a foreign substance, such as bee venom, pet dander, pollen, or food that does not cause a reaction in some people. When someone is exposed to something they are allergic to, a protein from the allergen interacts with the antibodies on their immune cells.

The human body naturally produces antibodies. When people have allergies, their immune system makes antibodies that identify a particular allergen as harmful, even though it is not. As they come into contact with the allergen, the reaction from their immune system can inflame their airways, sinuses, skin, or digestive tract.

There is a form of severe, life-threatening allergic reaction called anaphylaxis. This condition requires immediate medical treatment, such as prompt injection of epinephrine or a trip to a hospital emergency room.

Can Exercise Trigger Anaphylaxis?

About 2% of people from Western countries experience anaphylaxis, and 5-15% of the cases are due to exercise. Exercise can be associated with a rare and potentially fatal syndrome called exercise-induced anaphylaxis. Unlike ordinary allergic reactions, this condition is not necessarily antibody-mediated, but exercise serves as a triggering factor while the immune cells are still activated.

Exercise alone is enough to trigger an allergic reaction in some people, although its mechanism remains unknown. In the study "Exercise-Induced Anaphylaxis: An Update on Diagnosis and Treatment," researchers suggest that exercise causes a release of endorphins, which triggers some immune cells to release chemicals like histamine.

The symptoms of exercise-induced anaphylaxis can begin during any stage of physical activity. These include generalized itchiness, difficulty breathing, facial swelling, coughing, and flushing. It could even involve the cardiovascular system and cause a drop in blood pressure, making a person feel lightheaded or dizzy.

Other people experience food-dependent exercise-induced anaphylaxis. For these people, eating a specific type of food before working out can cause symptoms like wheezing or hives, even if they do not react to that food when lounging. Some common food triggers for this type of allergy include beef, egg, mushrooms, shellfish, and nuts. Experts theorize that working out makes the gastrointestinal tract more permeable, allowing the allergens to come into better contact with the immune system.

Diagnosing exercise-induced anaphylaxis comes with some challenges. Allergists have to decide whether the reported event is consistent with anaphylaxis and determine possible triggers while ruling out other related health conditions.

Experiencing exercise-induced anaphylaxis does not mean a person cannot work out anymore. A person needs to know the level at which the anaphylactic event happened. They need to understand the importance of stopping all exertion at the onset of symptoms. In other words, individuals who suffer from exercise-induced anaphylaxis need to discover new ways to move their bodies.