Exercise-Induced Anaphylaxis

By admin On Dec 11, 2023

Ovid: 5-Minute Sports Medicine Consult, The

Robert G. Hosey

Basics

Description

Distinct form of physical allergy characterized by a spectrum of exercise-induced symptoms ranging from mild skin symptoms such as pruritus and urticaria to angioedema, hypotension, syncope, and death.
A subgroup may develop food-dependent exercise-induced anaphylaxis (EIA).

Epidemiology

Incidence

Incidence seems to be increasing (1). A few deaths have been attributed to EIA in the literature (2).
Predominant gender: Female > Male (∼2:1) (1).

Prevalence

∼1,000 cases have been reported (3).

Risk Factors

Previous episodes
Atopic individuals may be at slightly increased risk.
Associated factors include:
- Ingestion of certain foods or medications (particularly aspirin or NSAIDs) before exercise may be a predisposing factor.
- Hormonal fluctuations during menstrual cycle may play a role in women with EIA (1).
- Family variant may exist.

General Prevention

Preventive medications include (3):

Nonsedating antihistamines on a daily basis have been shown to be at least partially effective in prevention of symptoms (cetirizine 5–10 mg PO every day, loratidine 10 mg PO every day) (3)[C].
Cromolyn sodium metered-dose inhaler (MDI) 2–4 puffs q.i.d. may be helpful.
Possible role for use of leukotriene inhibitors (montelukast 10 mg PO in the evening, zafirlukast 20 mg PO b.i.d.)
Some clinicians advocate for avoiding antihistamines because they may block cutaneous manifestations of EIA that often serve as a “warning” of impending anaphylaxis (1,4)[C].
Avoid food/medication triggers.

Etiology

Release of histamine and tryptase by mast cells has been implicated as a possible cause of EIA.

Commonly Associated Conditions

Eczema
Asthma

Diagnosis

Careful clinical history documentation of attacks is often required to make a diagnosis.

History

Transient exercise-induced itching and cutaneous erythema ± urticaria is suggestive of EIA.
Progression of these symptoms to dyspnea, dizziness, GI colic, or syncope is further suggestive of EIA.
History of previous EIA
Identify possible provocative agent: Urticaria with warm shower or anxiety is consistent with cholinergic urticaria. Cold, ultraviolet rays, or water also may induce urticaria. Diagnosis may require an exercise diary.
Identify any ingestions prior to exercise: Specific food or NSAID may be a trigger.
EIA does not occur with every bout of exercise but may occur at any level of physical activity.
Signs and symptoms include:
- Generalized itching
- GI colic
- Headache
- Choking sensation
- Urticaria or angioedema with hypotension or respiratory obstruction is hallmark of classic EIA.
- Patient may present in full anaphylactic shock.

Physical Exam

Assess ABCs:
- Hypotension or respiratory difficulty may signify impending anaphylactic shock.
- Dermatologic examination may reveal wheals.
- Identifying urticarial size and presence of angioedema aids in diagnosis (5).

Diagnostic Tests & Interpretation

Lab

Abnormal laboratory tests include elevated serum histamine and serum tryptase levels.
Serum tryptase levels should be determined within 2–3 hr of the event (2).

Diagnostic Procedures/Surgery

Passive warming test (eg, warm shower or sauna) can be helpful in differentiating cholinergic urticaria from EIA.
Exercise challenge test using a treadmill or stationary bike can be performed. A positive test (reproduction of symptoms and urticaria) is helpful in diagnosis, but a negative test does not exclude a diagnosis of EIA because reproducibility of symptoms is variable. Emergency equipment should be immediately available if exercise test is performed.
Allergy testing for potential food and common allergen triggers should be done in all patients with EIA.

P.141

Differential Diagnosis

Cholinergic urticaria
Exercise-induced asthma
Environmental allergy

Treatment

Pre-Hospital

ABCs
SC administration of 0.3–0.5 mL epinephrine 1:1,000 if systemic symptoms of anaphylaxis are present; then call 911.
Trendelenburg position

ED Treatment

Treat symptoms of anaphylactic shock as necessary in appropriate medical setting (eg, fluid support for hypotension, assisted ventilation for respiratory obstruction).

Additional Treatment

General Measures

Cease physical activity if any symptoms arise.
Avoid exercise for 4–6 hr after eating.
Avoid anti-inflammatory drugs before exercise.
Always exercise with a partner and carry injectable epinephrine.
Possible role for desensitization to physical activity

Ongoing Care

Follow-Up Recommendations

Referral to an allergist for identification of possible associated triggers may be beneficial.
Follow-up to assess recurrence of symptoms and success of drug therapy

Patient Education

Advise patient on Epipen use (should have access to one at all times).
Renew Epipen annually.
Advise patient to avoid any triggers, if known.
Recommend wearing a medical alert device.

References

1. Castells MC, Horan RF, Sheffer AL. Exercise-induced anaphylaxis. Curr Allergy Asthma Rep. 2003;3:15–21.

2. Sheffer AL, Soter NA, McFadden ER, et al. Exercise-induced anaphylaxis: a distinct form of physical allergy. J Allergy Clin Immunol. 1983;71:311–316.

3. Briner WW. Physical allergies and exercise. Clinical implications for those engaged in sports activities. Sports Med. 1993;15:365–373.

4. Schwartz LB, Delgado L, Craig T, et al. Exercise-induced hypersensitivity syndromes in recreational and competitive athletes: a PRACTALL consensus report (what the general practitioner should know about sports and allergy). Allergy. 2008;63:953–961.

5. Nichols AW. Exercise-induced anaphylaxis and urticaria. Clin Sports Med. 1992;11:303–312.

Additional Reading