Anaphylaxis | Causes & Risk Factors


What causes anaphylaxis?

Anaphylaxis is most often caused by exposure to an allergen. Normally, when you are exposed to an allergen, your immune system produces antibodies to help you “fight” the allergen. These antibodies are the cause of normal allergy symptoms—normal allergy symptoms aren’t life threatening. However, sometimes your immune system can overreact to an allergen and cause a very severe allergic reaction—this can lead to anaphylaxis and is very dangerous.

Allergens and substances that may lead to anaphylaxis include the following:

  • Foods such as shellfish, nuts, peanuts, eggs, and fruits
  • Medicines such as antibiotics, aspirin, over-the-counter pain relievers (such as ibuprofen), allergy shots, and contrast dye for imaging procedures
  • Latex or rubber found in surgical gloves, medical supplies, and many products in your home
  • Insect stings, especially from bees, wasps, hornets, yellow jackets, sawflies, and fire ants


A Practical Guide to Anaphylaxis by TW Tang, M.D. (American Family Physician October 01, 2003,

Written by editorial staff

Reviewed/Updated: 04/14
Created: 11/04