Ongoing Task Forces

Exercise-induced anaphylaxis (EIAn)

Introduction
Exercise-induced anaphylaxis (EIA) is a rare, unpredictable, potentially fatal, syndrome characterised by anaphylaxis associated with exercise. Anaphylaxis is associated with a mortality rate of between 1-2%; importantly, some 5-15% of anaphylactic episodes are caused by /or are associated with exercise. EIA may occur independently of food allergen ingestion, or may require the ingestion of a food allergen around the time of exercise, known as FDEIA. The symptoms of FDEIA may vary in severity but reassuringly, fatalities are rare.  EIA occurs in all ages, in both sexes, and is more common in atopic individuals.  EIA is generally reported following sub-maximal exercise of a relatively short duration; this fact alone eliminates the majority of the proposed pathophysiological mechanisms. EIA has been described in high-performance athletes and in individuals undertaking only occasional exercise. Even regular physical activity e.g. raking garden leaves, has been reported as a trigger for EIA.

There are now more than one hundred reviews on the topic of EIA (food dependent and non-food dependent) upon which much of our current knowledge of the condition is based. A recent publication has reviewed some of the current working hypothesis for (FD)EIA and indicated that many of the hypotheses are inappropriate for the physiological changes that occur during exercise and actually occur within the time frame and exercise intensity domain during which EIA reportedly occurs.

One example of the disparity between EIA and contextual exercise physiology is the much cited study proposing that exercise-induced increased gastro-intestinal permeability is a means through which EIA may be triggered with larger molecules - such as allergenic peptides - having greater access to the gut associated immune system. However, it has also been reported that small intestinal permeability was not altered by 60 mins of exercise at 40% and 60% of maximal oxygen uptake compared with rest; only when exercise was performed at much higher intensities (80% maximal oxygen uptake) for an hour did small intestine permeability become increased, even though there was no evidence of enhanced gastric permeability.  Indeed, some research indicates a reduction in permeability with light/moderate exercise.  Although, alterations in gut integrity and permeability have been reported at low intensities this only occurs during very prolonged exercise such as a long distance triathlon (> 8 hours of continuous exercise) hence, not within the short duration of exercise required initiate EIA.

Aim of the Task Force
1. To examine and determine the scientific merit of the current working hypotheses in the context of exercise-physiology and immunology
2. Provide a Position Statement on pathophysiological mechanisms underlying EIAn and future research directions.

EAACI Task Force experts

Les Ansley (IGAAS board)

UK

Matteo Bonini (Chair IGAAS)

Italy

Luís Delgado

Portugal

Stefano Del Giacco

Italy

George du Toit

UK

James Hull

UK

Musa Khaitov

Russia

Marcin Kurowsky (Secretary IGAAS)

Poland

André Moreira

Portugal

Paula Robson-Ansley

UK

Last updated 07 November 2014