What Is Anaphylaxis?

Anaphylaxis is a severe allergic reaction. Things that can cause allergic reactions are called allergens.

Anaphylaxis (pronounced: an-eh-fil-AK-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?

Allergic reactions can cause:

  • trouble breathing
  • throat tightness or feeling like the throat or airways are closing
  • hoarseness or trouble speaking
  • wheezing
  • nasal stuffiness or coughing
  • nausea, belly pain, vomiting, or diarrhea
  • trouble swallowing
  • fast heartbeat or pulse
  • skin itching, tingling, redness, or swelling
  • hives
  • a feeling like something bad is about to happen
  • pale skin
  • passing out

Anaphylaxis can cause different symptoms at different times. It's considered anaphylaxis if someone has:

  • any severe symptoms, such as trouble breathing, repeated vomiting, passing out, or throat tightness
    or
  • two or more mild symptoms, such as hives and vomiting or coughing and belly pain

The person needs treatment right away.

How Is Anaphylaxis Treated?

Someone with anaphylaxis needs help right away. The reaction can get worse very quickly. So doctors usually want people with allergies to carry injectable medicine called epinephrine. Epinephrine enters the bloodstream and works quickly against serious allergy symptoms.

Doctors prescribe epinephrine auto injectors. These should always be with the person with allergies, including at school, sports, jobs, and other activities. The auto injector is small and easy to use.

If you're prescribed epinephrine, the doctor will show you how to use it. Always have two auto injectors with you in case one doesn't work or you need a second dose.

Your doctor also might instruct you to take antihistamines in some cases. But always treat a serious reaction with epinephrine. Never use antihistamines instead of epinephrine in serious reactions.

What to Do if You Have Anaphylaxis

Give yourself epinephrine right away if you start to:

  • have trouble breathing
  • feel tightness in your throat
  • feel faint
  • have two or more milder allergic symptoms together (like hives with coughing)

Don't try to use an inhaler or antihistamine and wait to see what happens. Go straight for the epinephrine! Seconds count during anaphylaxis.

If you have signs of a serious allergic reaction:

  1. Use the epinephrine auto-injector right away. Then call 911. 
  2. Lay down with your legs raised while you wait for the ambulance.
  3. Go to the emergency room, even if symptoms improve after epinephrine. You must be under medical supervision for several hours. This is because a second wave of serious symptoms (called a biphasic reaction) often happens. You can get more treatment at the emergency room, if you need it.

What Else Should I Know?

Being prepared can help you stay safe:

  • Carry two epinephrine auto injectors with you at all times. Epinephrine can be a lifesaver.
  • Avoid the things you are allergic to.
  • Let friends, teachers, and coaches know about your allergies and how they can help you if you have a reaction.
Back to Articles


Related Articles

5 Ways to Be Prepared for an Allergy Emergency

Quick action is essential during a serious allergic reaction. It helps to remind yourself of action steps so they become second nature if there's an emergency. Here's what to do.

Read More

Shellfish Allergy

Shellfish allergies can be serious - and shellfish can appear in some surprising foods and products. Read about shellfish allergy and what to do when a reaction is severe.

Read More

Bug Bites and Stings

Generally, insect bites and stings are harmless. Find out how to keep pests from ruining your fun.

Read More

Nut and Peanut Allergy

Peanuts are one of the most common allergy-causing foods, and they often find their way into things you wouldn't imagine. Learn the facts on living with a nut or peanut allergy.

Read More

My Friend Has a Food Allergy. How Can I Help?

Although food allergies are more common than ever, people who have them may feel different or embarrassed. A good friend can really help.

Read More

Food Allergies

Doctors are diagnosing more and more people with food allergies. Knowing what to expect and how to deal with food allergies can make a big difference in preventing serious illness.

Read More

Allergy Testing

Doctors use several different types of allergy tests, depending on what a person may be allergic to. Find out what to expect from allergy tests.

Read More

Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2020 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.

Search our entire site.