Anaphylaxis: How to Recognize a Severe Allergic Reaction and Respond

Signs of Anaphylaxis

Symptoms can progress rapidly, and a person doesn't need all of them. Some people experiencing anaphylaxis have no skin symptoms at all.

• Difficulty breathing or wheezing
• Swelling of the lips, tongue, face, or throat
• Hives or widespread skin reactions
• Dizziness, fainting, weakness, or signs of shock
• Vomiting or abdominal pain
• Confusion or a change in responsiveness

Common Triggers

Someone can experience anaphylaxis even if they've never had a severe reaction before.

• Foods: peanuts, tree nuts, shellfish, milk, eggs, soy, wheat
• Insect venom
• Certain medications
• Latex and other known allergens

What to Do: Epi, 911, Monitor

• Act immediately — don't wait to see whether symptoms improve.
• Use epinephrine. It is the first-line treatment; help the person administer their prescribed auto-injector according to their instructions.
• Call 911, even if symptoms start improving after epinephrine.
• Position them safely: lying down if tolerated, sitting up if breathing is hard, on their side if vomiting.
• Stay and monitor breathing and responsiveness. If they become unresponsive and aren't breathing normally, start CPR and use an AED.

Antihistamines Are Not a Substitute

Antihistamines may ease itching or hives, but they do not treat airway swelling or low blood pressure. The CDC identifies epinephrine as the first and most important treatment for anaphylaxis.

Never delay epinephrine to see whether an antihistamine works.

If Symptoms Improve

Improvement doesn't mean the emergency is over. Symptoms can return after the initial reaction appears to resolve, which is why emergency evaluation is still necessary.

Some people are instructed by their provider to use a second dose of epinephrine if symptoms continue or return — follow their emergency action plan and the dispatcher's guidance while waiting for EMS.