Serious Allergic Reactions (Anaphylaxis)
en español: Reacciones alérgicas graves (anafilaxia)
Medically reviewed by: Hillary B. Gordon, MD
What Is Anaphylaxis?
Anaphylaxis is a severe allergic reaction that can be life-threatening. Things that can cause allergic reactions are called allergens.
Anaphylaxis (pronounced: an-eh-fih-LAK-siss) most often happens during allergic reactions to:
- foods
- insect stings
- medicines
- latex
Anaphylaxis can be scary. But being prepared will help you treat a reaction quickly.
What Are the Signs & Symptoms of Anaphylaxis?
Severe allergic reactions can cause:
- trouble breathing
- throat tightness or feeling like the throat or airways are closing
- hoarseness or trouble speaking
- wheezing or cough
- nasal stuffiness
- nausea, belly pain, vomiting, and/or diarrhea
- trouble swallowing or drooling
- low blood pressure
- skin itching, redness, or swelling
- hives
- a feeling like something bad is about to happen
- passing out
Anaphylaxis can cause different symptoms at different times. An allergic reaction is considered anaphylaxis if someone has:
- any severe symptoms, such as trouble breathing, repeated vomiting, passing out, or throat tightness
or