A severe allergy kills in minutes, and there is only one treatment. Everything else — antihistamines, cortisone, waiting to see — is among the causes of death.
ACT
1. Recognise it. After a contact — food, insect sting, medicine —, two things at once that come on fast:
- The skin: hives, blotches, swelling of the face, lips or eyelids, itching palms and scalp.
- and one of the following two: Breathing: tight throat, hoarse voice, trouble swallowing, wheezing, coughing, shortness of breath. or circulation: paleness, cold sweat, feeling faint, dizziness, loss of consciousness.
Throat swelling or a drop in blood pressure without a rash is still anaphylaxis. The skin signs can be missing.
2. Inject adrenaline immediately. If there's an auto-injector — theirs, someone else's, one from a kit —, use it without waiting to see whether things get worse.
Outer side of the thigh, halfway down, through clothing if needed. Hold it in place for a few seconds depending on the model, then massage briefly. It's safe: giving adrenaline to someone who didn't need it kills nobody; not giving it to someone who did, does.
3. Lay the person down with their legs raised. This is a life-saving step, not a comfort.
Never let them sit up or stand, even if they ask, even if they breathe better sitting. Deaths are documented in people who sat up or got up to go to the toilet after improving: the heart suddenly empties. If they can't bear lying flat because of their breathing, half-sitting is allowed, but the legs stay up and nobody stands.
Unconscious and breathing: on their side.
4. Call for help. Always, even if they're getting better.
5. Second dose after five minutes if nothing improves, in the other thigh. Most kits contain two for this reason.
6. Watch them for hours. Roughly one reaction in five is biphasic: it comes back one to twelve hours later, sometimes with no new contact, and sometimes more violently. Don't leave the person alone and keep the adrenaline within reach.
ADAPT
You have no adrenaline. Lay them down with legs raised, call for help, remove the cause if possible — a wasp sting is scraped off with a fingernail or a card, not pinched —, and cool the area. Antihistamines and cortisone don't treat anaphylaxis: they take tens of minutes to act on the rash and do nothing for the throat or the blood pressure. Give them if you have them, but don't rely on them, and never treat them as the answer.
It's a sting in the mouth or throat. Even without an allergy, local swelling can close the airway. Ice to suck on, sitting position, emergency help immediately.
It's a child. Same steps, with a child-dose auto-injector if available. If you're unsure between two doses, the adult one is still better than nothing.
The person has asthma. A clearly higher risk of a severe, fatal reaction. Adrenaline comes before the inhaler; the inhaler comes after, not instead.
It's a known allergy. Then the real work is done beforehand: two auto-injectors, always, within their expiry date, and people around who know where they are and how to use them. An auto-injector in a drawer that nobody knows how to use is useless. Do a calm run-through with the training device.
You're not sure it's anaphylaxis. Inject. The balance of benefit and risk isn't ambiguous: hesitation is the main factor in deaths in every published series.
UNDERSTAND
What happens
The immune system recognises a substance it has decided to treat as an enemy and triggers a massive release of chemical messengers, histamine first among them, throughout the body.
Three effects at once, and each one can kill:
- Blood vessels widen and become leaky. Plasma escapes into the tissues and the circulating volume collapses: that's shock.
- Tissues swell, including the tongue, the larynx and the airways: that's suffocation.
- The airways tighten.
Why adrenaline and nothing else
It acts on all three mechanisms at once, within minutes: it tightens the blood vessels (raising blood pressure and reducing swelling), opens the airways, and slows the release of the messengers.
No other readily available product does that. Antihistamines block a single messenger, on a single effect, with a long delay. Cortisone takes hours and serves to limit a relapse, not the attack itself.
And here's the deciding point: injected into the thigh muscle, it's absorbed much faster than in the arm or under the skin. It isn't a protocol detail; it's the difference between acting in five minutes and acting in twenty.
Why the position
In anaphylaxis, blood pools in the outer parts of the body and the heart fills poorly. Standing or sitting, gravity makes that filling problem worse; lying down with legs raised gives it volume back.
It's a simple mechanism, it's free, and it's in every guideline for a reason: people die from changing position at the wrong moment.
For the general examination of a casualty, see Examining a casualty; for poisonings that sometimes look like an allergy, Poisoning.