Anaphylaxis: Causes & Triggers

Reviewed by Rafeul Alam, MD, PhD
An anaphylactic reaction is often triggered by an allergen exposure. An exposure may occur through injection, swallowing, inhaling or skin contact.

Injected Allergens

Include bee, hornet, wasp and yellow jacket stings, and allergen extracts used for diagnosis and treatment of allergic conditions. Antibiotics such as penicillin can trigger a reaction by injection or ingestion (swallowing).


Ingested Allergens

A severe reaction caused by a food allergy occurs after eating that particular food, even a small bite. Foods that most commonly cause anaphylaxis are peanuts, seafood, nuts and, in children, eggs and cow's milk. Skin contact with the food rarely causes anaphylaxis.


Inhaled Allergens

An anaphylactic reaction from an inhaled allergen is rare. An example is a latex-allergic person who inhales particles from rubber gloves or other latex products.


Multiple Factors

For some people, two or more factors may be needed to cause anaphylaxis. It has been recognized that an anaphylactic reaction can occur if a person eats a certain food and then exercises. Neither the food alone nor exercise alone causes any problem, but the two together do.


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