People often manifest justified concerns about how serious an allergic reaction can be. A life threatening allergic reaction is also called anaphylaxis and is a severe reaction to a specific allergen, or what may be called an allergic trigger. Possible allergic triggers are all around us in food, stinging insects, and medication. Exercise can also induce anaphylaxis. Sometimes a severe allergic reaction has no apparent cause and is what is called idiopathic anaphylaxis. An awareness that anaphylaxis can cause death suddenly should alert people to be more careful about potential allergens.