What Is Exercise-Induced Anaphylaxis?

Overview

Exercise-induced anaphylaxis (EIA) is considered a rare and serious form of physical hypersensitivity reaction connected to exercise. EIA may involve the skin, respiratory tract, gastrointestinal tract, and cardiovascular system, causing itching, redness of the skin, urticaria, angioedema or circulatory failure. 

The prevalence of EIA is more significant in females assigned at birth than males assigned at birth, with a ratio of 2:1. It may occur in people from ages 5 to 75 years.  EIA may be provoked before exercise- by the intake of food (Food-dependent EIA), medicines, or any other physical activity.¹ 

Causes

Certain triggering factors may give rise to EIA:

Food-dependent exercise-induced anaphylaxis (FDEIA) 

This occurs when a particular food or any food is consumed 4-6 hours before the physical activity. It can be triggered by various foods, and at times the trigger remains undetermined, requiring the individual to abstain from eating anything for the preceding 4 to 6 hours of exercise (termed as non-specific FDEIA). When the triggering foods are determined, then the person should keep away from these specific foods before exercising.³ 

Consuming specific foods in conjunction with exercise

Individually, exercising or food consumption cannot show symptoms. Many food items are seen to trigger EIA, such as fish, pork, alcohol and many others. Food adulterated with aeroallergens like dust mites and Penicillium mould are included as well. Some people may be allergic to multiple food items, and when taken together, their consumption may result in EIA.³

Other potential triggers

• Cow’s milk-dependent events of EIA may arise when cow’s milk is desensitised¹
• Physical activities: Jogging, aerobics, racquetball, walking, tennis, dancing, bicycling, etc. Mild to moderate activities depending on person-to-person
• Environmental factors: Cold or hot temperatures and humidity.
• Drugs: NSAIDs like aspirin and other medicines
• Genetic factors: Autosomal dominant inheritance
• Menstrual period
• Others: Dental amalgam, pollen season^1,4

Signs & symptoms

In children, EIA may occur in either mild or exhausting situations. The symptoms vary in people based on the magnitude of exercise done and the quantity of food consumed. In food-dependent EIA, it may occur within a few minutes to hours of eating or eating after exercise.

EIA symptoms are very critical, resembling anaphylactic reactions, seen rarely in adults. These may show up usually in under 30 minutes post-exercise (90% of cases) and may continue for 24-48 hours (biphasic anaphylaxis).⁴

EIA may include four stages.

• Prodromal: Fatigue, prostration, generalized itching, and erythema.
• Early: Generalized skin hives (urticaria).
• Fully developed: Gastrointestinal features, abdominal pain, nausea, vomiting, upper respiratory blockage, difficulty breathing, wheezing of neck, and choking.
• Late: Frontal headache, fatigue.

Other symptoms 

• Lower airway features: dyspnea, dysphagia, and chest tightness
• Cardiac casualties: collapse, altered consciousness
• Flushing, hypotension, angioedema, diaphoresis. ¹ 

Diagnosis

Accurate diagnosis is vital for preventing needless dietary limitations, thereby encouraging secure physical activities for individuals with EIA (triggering causes like food) and controlling EIA symptoms. 

A thorough medical history and physical examination describing the clinical features help find the causative factor, although records of food-related reactions are not precise.

Skin prick tests/Circulating IgE antibodies of the various consumed foods prior to physical work aids in recognition of the triggering food item: Positive test for specific FDEIA and negative test in case of non-specific FDEIA or EIA.

When medical history and IgE tests prove uncertain, an Open Challenge test is done with medical guidance and with the availability of appropriate medical resources to treat anaphylactic reactions. In case of an adverse reaction, blood pressure monitoring is mandatory, and treatment is given. 

Exercise challenge tests are done in kids, such as free running (with guidelines in agreement to exercise-induced bronchoconstriction), which include physical activity for not less than 6 minutes to acquire 80% of the maximum heart frequency adequate for the age. For adults, it is done with guidelines compatible with ischaemic heart disease to recognize EIA.⁴ 

Controlled tests: Fasting exercise tests, exercise-suspected food combined tests, and exercise tests accompanied by triggering causes like drugs and extreme environmental conditions may be done to confirm the diagnosis, along with specialized tests. Triggering factors are to be ignored in cases of positive tests.

Differential diagnosis may include Cholinergic urticaria, Exercise-induced bronchoconstriction, Hyperventilation syndrome, Panic or vasovagal attacks, Vocal cord dysfunction, Hereditary angioedema, Cold urticaria, Non-exercise food allergy, cardiac and neurological diseases.⁴

Management and treatment

Avoidance of triggers

The sufferers of EIA, their families, and caregivers should be properly guided and trained to recognize relevant triggers (foods, drugs, allergens, etc.) to prevent them and to manage these events when required, especially in children, because parents cannot limit their kids' physical exhaustion. Kids with EIA are advised to be involved in physical activities 4 hours after consumption of suspected food and keep away from that food for another 1 hour after exercise; such kids should be motivated to engage in physical activities for positive outcomes.

Medical management

Individualised written medicines for emergencies and the corresponding management plans should be prepared; the people around them should be aware of it.

Prescribed medicines like sodium cromoglycate, H2-antihistamines, leukotriene modifiers, steroids, or sodium bicarbonate have been beneficial in some cases.

Individuals with EIA and their caregivers should always have self-injectable epinephrine ready for use and should know its usage.

In case of an EIA attack, the patient is held in a supine position and given self-injectable epinephrine accompanied by H2-antihistamines and steroids. If required, immediate hospitalisation.⁴

Other than the abovementioned management, vulnerable people should never exercise alone and should always be accompanied by trained individuals in treating anaphylactic reactions.

Risk factors

The factors that cause exhaustion, like aerobic exercise, jogging, and brisk walking in EIA sufferers, can induce its attack. Also, suspected food items (seafood, wheat, etc.), drugs (NSAIDs), alcohol, contact with pollen, hot or cold climate, humidity, and menstruation days could be dangerous depending on different individuals and their triggers.⁴

Complications

• Severe anaphylaxis
• Cardiac complications: fainting, altered consciousness
• Recurring symptoms¹
• Death if left untreated in critical cases (rare)

FAQs

How can I prevent EIA?

1. Susceptible Individuals should recognize and keep away from their corresponding triggering factors like foods, climate & medicines.
2. Adjusting food timings according to the exercise schedule aids in minimizing risk.
3. Preplanned emergency management with epinephrine injections and regular communication with healthcare professionals is crucial for a safer and more active lifestyle with EIA.⁴

How common is EIA?

The prevalence of EIA is relatively sporadic and varies in different populations- more significant in assigned females than assigned males at birth, with a ratio of 2:1. It may occur in people from 5 to 75 years.¹

What can I expect if I have EIA?

A person having EIA may suffer severe allergic reactions like itching, hives, breathing difficulties, and potentially life-threatening issues.¹

When should I see a doctor?

If you experience symptoms like itching, hives, or choking during or after exercise, it is vital to reach a doctor immediately. Timely evaluation ensures accurate diagnosis and sets up an effective management plan. ¹

Summary

Exercise-induced Anaphylaxis (EIA) is a sporadic but deadly allergic condition distinguished by the onset of severe allergic reactions during or after physical activity. This specific form of anaphylaxis presents with symptoms including skin reactions, respiratory distress, gastrointestinal complications, and cardiovascular issues. EIA is triggered by distinctive factors such as certain foods, environmental conditions, medications, etc. The diagnosis of EIA is challenging due to its resemblance to other conditions, necessitating a comprehensive evaluation. Preventive measures point out recognising and avoiding triggers, taking precautions before exercise, and being accompanied by an emergency plan if required. This condition impacts a person’s daily life, exercise habits, and emotional well-being. Support from healthcare professionals is crucial for helping individuals cope with the challenges of EIA and lead fulfilling lives while dealing with this serious condition.