This is simplified information about exercise induced anaphylaxis – there are more resources available at the bottom of the page for further reading for those who are interested in knowing more.
What is it?
Exercise Induced Anaphylaxis (EIA) is a condition in which moderate to extreme exercise causes anaphylaxis in the patient (and in extreme cases even mild exercise cause symptoms). Many of these cases are further described as Food-Dependent Exercise Induced Anaphylaxis (FD-EIA), where a patient has eaten an allergen and then exercised, causing symptoms.
What are the symptoms of exercise induced anaphylaxis?
Symptoms of EIA may start at any stage of exercise or just after it, but in most patients, they begin within 30 minutes after initiating exercise. The condition has been described in some studies occurring up to 4 hours later.
Symptoms may include:
Warmth or Flushing
Pruritus (severe itching) or Urticaria (hives)
Angioedema (swelling of the body, hands, feet or face)
Upper Respiratory Obstruction and Collapse
Why do symptoms only occur with exercise?
In many cases a weakly positive skin prick for the causative allergen is found. Patients can consume the allergen safely as long as they are not exercising or exercise without eating the allergen and remain safe, it is only the combination which causes anaphylaxis.
Hypothesis for why this happens include:
Increased gastrointestinal permeability (where the cells of the intestines allow larger molecules, in this case allergens, to pass through to the gut)
Blood flow redistribution (where blood is diverted away from other organs to the muscles used in exercise).
Alterations in Blood Plasma.
Changes in Osmolarity and pH of the blood.
Food Dependent Exercise Induced Anaphylaxis
In comparison FD-EIA, ingestion of the causative food usually precedes exercise by several minutes or even hours. There are some cases where FD-EIA may also occur if the food is ingested soon after the completion of exercise. The triggering factor is important, so that the condition can be properly managed.
Animal allergy, dust mite allergy, pollens and certain drugs have also been known to be part of the trigger for this form of anaphylaxis.
What foods are involved in exercise induced anaphylaxis?
Cereals are the most common trigger food involved with EIA, the most prominent being wheat and buckwheat.
Cases of EIA with shellfish and grape have also been recorded as well as tree nuts, soya and fish.
Please visit the Food Index of this site if you are interested in the cross reactivity of a specific food, there are lots of resources dedicated to cross reactivity.
Wheat Dependent Exercise Induced Anaphylaxis
This is a condition within FD-EIA which is well studied as it has been suggested in some studies that over 50% of FD-EIA cases are triggered by wheat allergens (see reference section).
How is EIA diagnosed?
For FD-EIA, diagnosis can start with skin prick tests (or blood tests) for possible allergens. The result may only be a mild positive.
WD-EIA can be diagnosed the same way, but with IgE for omega-5-gliadin (the major wheat allergen) specifically tested for.
How can EIA be managed?
Antihistamines should never be used as an alternative to epipens for those suffering from anaphylaxis. It is recommended in the UK that in these cases that two epipens are prescribed in case of unit failure or a biphasic reaction.
Avoidance of exercise after your trigger allergen is consumed or avoidance of your trigger allergens if you intend to exercise. Management of the condition varies from case to case depending on the severity, but should be discussed with your healthcare provider.
A higher chance of EIA has been linked to:
A warm environment
Knowing which allergens bring the condition on, plus any of the additional factors as above, can all help in managing the condition.
Exercise Induced Anaphylaxis should not be confused with cholinergic urticaria, which is chronic hives, which usually starts with an elevated body temperature.
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