Anaphylaxis: The Quick Reference
Anaphylaxis: the whole thing in five minutes, for when you want the numbers and nothing else.
A severe, rapid-onset allergic reaction affecting breathing or circulation.
Key takeaways
- Only effective treatment: intramuscular adrenaline, into the outer thigh
- Second dose: after 5 minutes if there is no improvement
- Most useful single change: Use the adrenaline auto-injector immediately at the first sign.
- Commonest mistake: Standing the person up or letting them walk, which can be fatal.
- See a doctor if any of the signs under "When to speak to a doctor" below apply to you.
The numbers, in one place
| Measure | Figure |
|---|---|
| Only effective treatment | intramuscular adrenaline, into the outer thigh |
| Second dose | after 5 minutes if there is no improvement |
| Position | lie flat with legs raised; sit up only if breathing is difficult |
| Antihistamines | do not treat anaphylaxis and must never delay adrenaline |
| After adrenaline | always call 999 and go to hospital |
In one paragraph
Adrenaline is the only treatment that works and delay is the main cause of death, which makes recognition and speed the entire issue.
Worth doing
- Use the adrenaline auto-injector immediately at the first sign
- Carry two auto-injectors at all times
- Lie the person flat with legs raised unless breathing is difficult
- Check expiry dates and practise with a trainer device
Worth avoiding
- Standing the person up or letting them walk, which can be fatal
- Relying on antihistamines or an inhaler
- Waiting to see whether symptoms settle
Where to go next
- Anaphylaxis: What to Do, in Order
- Anaphylaxis: Common Myths and What Guidelines Say
- Anaphylaxis — the reference entry
- Food Allergy: What the Evidence Actually Says
- What the Guidance Really Says About Hay Fever and Pollen
When to speak to a doctor
Call 999 immediately for swelling of the lips, tongue or throat, difficulty breathing or swallowing, a hoarse voice, wheeze, widespread rash with faintness, or collapse. Use an adrenaline auto-injector straight away if prescribed, lie the person flat with legs raised, and give a second dose after five minutes if there is no improvement. Always go to hospital even if symptoms resolve, because they can return.
Where this comes from
- Resuscitation Council UK — anaphylaxis guidance
- NHS — Anaphylaxis
How this page was put together
Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarised or generalised beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.
Medical disclaimer
This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to a GP, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 999.
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