Anaphylaxis is a severe, sometimes life-threatening, allergic reaction. It affects multiple organs, including the heart and lungs.

It is important to seek medical care right away if you have symptoms of anaphylaxis.

Substances that cause anaphylaxis are often called allergens or triggers. Common triggers include:

  • Foods and food additives, especially eggs, peanuts, seafood, cow's milk, soy, fish, shellfish, seeds, and tree nuts
  • Insect stings or bites from bees, wasps, hornets, yellow jackets, and fire ants
  • Medicines (such as antibiotics, seizure medications, muscle relaxants)
  • Vaccines
  • Latex products (such as gloves, medical tubing, condoms)
  • Blood transfusion
  • Some pain medicines, especially narcotics

Allergic Reaction to Medication (Hives)
Hives Medication
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Some triggers, like dyes used in x-ray procedures, can cause a reaction similar to anaphylaxis.