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Anaphylaxis warning icon

Call your local emergency number if someone is having an allergic reaction with signs of anaphylaxis.

What is Anaphylaxis?

Anaphylaxis, also called anaphylactic shock, is an acute, life-threatening allergic reaction. The reaction affects different organs in the body, one or several at a time. Even if the initial symptoms are experienced mildly, there is a risk that they may rapidly turn into a serious and severe condition. Anaphylaxis can occur immediately or within minutes, depending on the route of exposure, and can worsen quickly.    


Anaphylactic shock is an acute life-threatening allergic reaction infographic

Anaphylaxis requires immediate medical attention and a trip to the emergency department. Because it can get so serious so fast, speedy treatment is incredibly important. This is why people with a known allergy carry epinephrine, usually in an auto-injector. 



Common anaphylaxis symptoms can include:

  • A sudden drop in blood pressure
  • Abdominal pain
  • Hives
  • Nausea and vomiting
  • Shortness of breath
  • Swelling around the eyes and the mouth 
  • Tingling and itching around the mouth
  • Weak and rapid pulse


The most common anaphylactic reactions are to foods, insect stings, and medications. Foods are the most common cause in children and young adults, while medications and insect stings are more common causes of anaphylaxis in older adults.1

Although anaphylaxis is rare and most people recover from it, it's important to know what caused—or what could cause this severe reaction. 

  1. Simons et al. “2012 Update: WAO Anaphylaxis Guidelines” Curr Opin Allergy Clin Immunol. 2012, 12:389–399.