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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medically reviewed by WellAlly Editorial TeamLast reviewed October 19, 2026Editorial policy
First Aid18 min read

Anaphylaxis First Aid

Published: October 19, 2026Updated: October 19, 2026

Anaphylaxis is a severe, rapid, and potentially life-threatening allergic reaction that impairs breathing and circulation. Immediate intervention with an epinephrine auto-injector is the primary and most vital treatment. Recognizing the signs and acting quickly can save a person's life.

Quick Summary

Inject epinephrine into the outer thigh immediately, call 911, and keep the person lying down with legs elevated unless they are having trouble breathing.

Important Medical Disclaimer

This guide is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with qualified healthcare providers for medical concerns.

Step-by-Step Guide

1

Administer Epinephrine Immediately

Locate an epinephrine auto-injector (such as an EpiPen or Auvi-Q) and inject it into the middle of the outer thigh muscle. It can be administered directly through clothing if necessary. Hold the device firmly in place according to device instructions (typically 2 to 3 seconds) before removing.

Important: Do not delay epinephrine to give oral antihistamines. Epinephrine is the only medication that can halt the progression of fatal airway swelling and shock.

2

Call Emergency Services (911)

Dial 911 or your local emergency number immediately after delivering the injection. Inform the dispatcher that the individual is experiencing severe anaphylaxis and that epinephrine has been given. Follow all additional instructions provided by the operator until help arrives.

Important: Even if the individual feels better after the injection, emergency medical transport to a hospital is required due to the risk of delayed complications.

3

Position the Person Properly

Lay the person flat on their back and elevate their legs approximately 12 inches to support blood pressure, provided this does not cause pain. If the person has severe respiratory distress, allow them to sit upright. If they are vomiting, nauseous, or unconscious, place them on their side in the recovery position.

Important: Do not allow the person to stand up, walk, or sit up abruptly, as sudden changes in posture can precipitate a lethal drop in blood pressure.

4

Remove the Trigger if Safe

If an insect stinger is visible, scrape it off the skin using a fingernail, dull blade, or credit card edge without squeezing the venom sac. Discontinue any offending food or environmental exposure. Avoid complex maneuvers that delay care.

5

Administer a Second Dose if Needed

Continuously monitor the person's breathing, alertness, and skin color. If symptoms fail to improve, worsen, or recur within 5 to 15 minutes, inject a second dose of epinephrine using a fresh auto-injector in the opposite thigh. Keep all used injectors to show paramedics.

6

Begin CPR if the Person Becomes Unresponsive

If the person becomes unresponsive, stops breathing, or is only gasping, immediately start cardiopulmonary resuscitation (CPR). Place your hands in the center of their chest and perform continuous chest compressions at a rate of 100 to 120 beats per minute until emergency medical personnel arrive.

Important: Do not attempt to give oral medications, fluids, or food to an individual experiencing severe respiratory difficulty or altered mental status.

Frequently Asked Questions

Can I give an oral antihistamine like diphenhydramine instead of epinephrine?
No. Oral antihistamines take 30 to 60 minutes to absorb and cannot reverse life-threatening swelling of the throat or dangerous drops in blood pressure. Epinephrine is the required first-line treatment.
What is a biphasic anaphylactic reaction?
A biphasic reaction is a second wave of anaphylactic symptoms that occurs hours after the initial reaction has cleared, without additional allergen exposure. Because of this risk, patients must be observed in a hospital setting.
Should I use an expired epinephrine auto-injector if no other option exists?
Yes. Clinical guidelines recommend using an expired injector during an emergency if no unexpired device is available, as it is likely to retain some potency and the risk of untreated anaphylaxis is fatal.
Can epinephrine be administered through thick clothing?
Yes. Autoinjector needles are designed to pass through typical clothing materials, including denim. Ensure the injection site is free from thick seams, zippers, or pocket contents like keys or phones.
  1. 1
    Mayo ClinicSource
  2. 2
    NHSSource
  3. 3
    National Library of Medicine - StatPearlsSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed October 19, 2026. · Read our editorial policy