How to help someone with a severe allergic reaction
Signs of a severe allergic reaction include swelling of the lips, tongue or throat, trouble breathing, wheezing, hives spreading fast, dizziness or fainting. Call your local emergency number, 911 in the US, and help the person use their own prescribed auto-injector exactly as its label shows, usually into the outer thigh. Keep them lying down, or sitting up if breathing is hard, and stay with them.
Why it matters: Severe reactions move fast, and helping someone use their own auto-injector matters.
In an emergency, call your local emergency number, 911 in the US, first. Reading a page is not training: take a certified class and practice on a manikin.
Steps
- Look for swelling of the face, lips or throat, trouble breathing, wheezing, spreading hives, vomiting or faintness.
- Call your local emergency number, 911 in the US, and say you think it is a severe allergic reaction.
- Ask whether they carry an auto-injector and help them get it out.
- Help them use it exactly as the label shows, usually into the outer thigh; it can go through clothing.
- Have them lie down with legs raised, or sit up if breathing is difficult.
- Follow the dispatcher's instructions if symptoms continue.
- Stay with them until help arrives, even if they seem better, and give the used device to the paramedics.
- Take a certified first aid class to practice with a trainer device.
Stop and call a professional if
- any sign of a severe allergic reaction: call your local emergency number, 911 in the US, even after the auto-injector is used
Common mistakes
- Waiting to see if it gets better before calling.
- Letting the person stand or walk around while faint.
- Using someone else's prescribed device on them.
Teach this to someone
A one page sheet for showing a friend, a teenager or a parent: what to say, what to show, and one question to check it landed.
Teach: How to help someone with a severe allergic reaction
What to say
Signs of a severe allergic reaction include swelling of the lips, tongue or throat, trouble breathing, wheezing, hives spreading fast, dizziness or fainting. Call your local emergency number, 911 in the US, and help the person use their own prescribed auto-injector exactly as its label shows, usually into the outer thigh. Keep them lying down, or sitting up if breathing is hard, and stay with them.
What to show
- Look for swelling of the face, lips or throat, trouble breathing, wheezing, spreading hives, vomiting or faintness.
- Call your local emergency number, 911 in the US, and say you think it is a severe allergic reaction.
- Ask whether they carry an auto-injector and help them get it out.
- Help them use it exactly as the label shows, usually into the outer thigh; it can go through clothing.
- Have them lie down with legs raised, or sit up if breathing is difficult.
- Follow the dispatcher's instructions if symptoms continue.
- Stay with them until help arrives, even if they seem better, and give the used device to the paramedics.
- Take a certified first aid class to practice with a trainer device.
Where it stops
Stop and call a professional if any sign of a severe allergic reaction: call your local emergency number, 911 in the US, even after the auto-injector is used.
Check question
Which is a sign of a severe allergic reaction?
Answer: Swelling of the lips or throat with trouble breathing. Airway swelling is a medical emergency.
Your checklist
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Quick quiz
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Related skills
Sources
- US national first aid guidelines for lay responders, 2025. Reviewed September 28, 2026.
Written in our own words from the sources above. It is general information, not advice for your situation; where a professional, your doctor or your lease says something different, follow them.
Last reviewed . First published .