Exercise-induced anaphylaxis

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What this article covers

• Overview

  Definition: exercise-induced anaphylaxis is anaphylaxis precipitated by physical exertion, often occurring only when exercise is combined with a cofactor such as a specific food.

• Epidemiology

  Uncommon but recognized: a notable cause of exertional anaphylaxis, more common in adolescents and young adults.

• Risk factors

  Culprit food ingestion before exercise: wheat most classically, also shellfish, celery, and others.

• Pathophysiology

  Exercise as a trigger or amplifier: exertion increases mast cell mediator release and gastrointestinal allergen absorption, lowering the threshold for degranulation.

• Clinical features

  Exertional onset: pruritus, flushing, and urticaria early in exercise, progressing to angioedema, wheeze, and hypotension.

• Differential diagnosis

  Anaphylaxis from an ingested allergen alone: food anaphylaxis independent of exercise (Anaphylaxis), reproducible on ingestion without exertion rather than only when exercise follows the meal.

• Diagnosis

  Diagnose clinically from the exertional trigger and cofactor pattern: the diagnostic basis is a history of anaphylaxis occurring during or shortly after exercise, meeting standard anaphylaxis…

• Management

  First, treat the acute attack as anaphylaxis: stop exercising immediately and give epinephrine 0.3 to 0.5 mg IM into the anterolateral thigh, repeated every 5 to 15 minutes, with IV fluids and airway support.

• Complications

  Fatal anaphylaxis: if epinephrine is delayed, especially when exercising alone.

• Prognosis

  Good with avoidance: identifying and separating cofactors from exercise prevents most attacks.

• Prevention

  Avoid exercise for 4 to 6 hours after the culprit food in food-dependent disease.