From the Guidelines
Exercise induces or increases an allergic response through several physiological mechanisms, including increased body temperature and blood flow, which cause mast cells and basophils to release histamine and other inflammatory mediators, as well as increased respiratory rate, leading to greater inhalation of potential allergens like pollen or pollution 1.
Physiological Mechanisms
The body's stress response during exercise releases stress hormones that can alter immune function and lower the threshold for allergic reactions. Additionally, exercise increases gut permeability, potentially allowing food allergens to enter the bloodstream more easily, which explains why eating certain foods before exercise can trigger reactions in some people 1. Exercise-induced sweating may also concentrate allergens on the skin, causing contact reactions.
Prevention Strategies
For those with exercise-induced allergies, prevention strategies include:
- Avoiding known trigger foods before exercise
- Exercising indoors during high pollen seasons
- Carrying emergency medication like epinephrine auto-injectors
- Gradually warming up to allow the body to adjust to increased activity levels
- Avoiding exercise for 4 to 6 hours after eating, especially for individuals with documented exercise-induced anaphylaxis after food ingestion 1
Management
Early recognition of the prodromal manifestations of exercise-induced anaphylaxis is extremely important, with discontinuation of exercise at the earliest symptom 1. The emergency management of exercise-induced anaphylaxis is the same as that of anaphylaxis of other causes, with the early administration of epinephrine being essential 1. Patients with exercise-induced anaphylaxis should carry epinephrine and should wear and/or carry Medic Alert identification denoting their condition, and have a companion with them when exercising who is versed in the use of an EpiPen 1.
From the Research
Mechanisms of Allergic Response
- Exercise can induce or increase an allergic response in susceptible individuals, with several conditions mediated by vasoactive substances, resulting in symptoms of urticaria and/or angioedema 2.
- Cholinergic urticaria and exercise-induced anaphylaxis (EIA) are two conditions that may occur as a direct result of exercise, with EIA typically presenting with generalized pruritus, flushing, and urticaria in association with vigorous physical exertion 2, 3.
- Mast cell degranulation and the release of histamine are thought to play a key role in the development of symptoms in exercise-induced anaphylaxis and urticaria 3, 4.
Types of Exercise-Induced Allergies
- Several types of physical allergies may affect exercising individuals, including:
- Cold urticaria
- Localized heat urticaria
- Symptomatic dermatographism (dermographism)
- Delayed pressure urticaria (angioedema)
- Solar urticaria
- Aquagenic urticaria 2
- Exercise-induced anaphylaxis (EIA) is a rare but potentially life-threatening condition that can occur in response to physical exercise, with symptoms including flushing, pruritus, urticaria, angioedema, and respiratory symptoms 5.
Management and Treatment
- Management of exercise-induced allergies may include patient education, selective avoidance, antihistamines, and induction of tolerance 2.
- Treatment of acute episodes of exercise-induced anaphylaxis includes cessation of exercise, administration of epinephrine, and antihistamines, as well as vascular support and airway maintenance 4.
- Long-term management of anaphylaxis includes identification and avoidance of triggers, patient education, and interventions to reduce allergen sensitivity, such as venom immunotherapy for Hymenoptera hypersensitivity 6.