Avoidance is crucial.

Anaphylaxis is unpredictable.1,2 When it comes to being prepared, avoidance of potentially life-threatening allergens is the critical first step to preventing a life-threatening allergic reaction; however, accidental exposure can still happen.1,3-5

Common anaphylaxis triggers

Allergens that induce anaphylaxis include food, biting or stinging insects, medications and latex; however, anaphylaxis is occasionally reported after direct exposure to radiocontrast media and can also occur after exercise (Table 1).3,6,7

Table 1. Causes of anaphylaxis3,6,7


  • Peanuts
  • Tree nuts (e.g., walnuts and pecans)
  • Fish
  • Shellfish
  • Milk
  • Soy
  • Eggs
  • Wheat

Biting or stinging insects

  • Stinging insects (e.g., honeybees, fire ants, yellow jackets, yellow hornets and paper wasps)
  • Less commonly, biting insects


  • β-lactams (e.g., penicillin)
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) (e.g., aspirin and ibuprofen)6
  • Biologic modifiers (e.g., cetuximab, infliximab and omalizumab)3



Radiocontrast media§

A diagnosis of idiopathic anaphylaxis is made when no allergic triggers can be identified based on history, negative skin tests and absent or undetectable serum-specific IgE levels. Every possibility of a hidden or previously unrecognized trigger should be ruled out before a diagnosis of idiopathic anaphylaxis is made.3,6,7

Certain risk factors may increase the likelihood and severity of an anaphylactic reaction; they are discussed in the “Identifying Anaphylaxis” section.6

*Peanuts, tree nuts, fish, shellfish, milk and eggs account for the greatest number of anaphylactic reactions in children; shellfish is the most common trigger in adults.8
Anaphylactic reactions induced by biting or stinging insects are more common in adults than in children.9
Anaphylaxis in response to a medication can occur in patients of any age, but is particularly common in middle-aged and older adults.6
§In some people, exercise and exposure to radiocontrast cause non-immune perturbations of mast cells and basophils, leading to anaphylaxis.5