Why the First Few Minutes Matter

Anaphylaxis is a severe allergic reaction that develops quickly — often within minutes of contact with a trigger, though occasionally up to an hour later. In the UK, the most common causes in adults are foods such as peanuts, tree nuts, shellfish and sesame, insect stings from wasps and bees, and medicines including penicillin and some anti-inflammatories. Latex and exercise can also be responsible.

Speed matters because anaphylaxis can move from mild to life-threatening in a very short time, and adrenaline works best when given early. Waiting to see whether things get worse is one of the most common and most dangerous mistakes. If you recognise the pattern below, act.

Skin Changes: Often the First Clue

Around four in five people having anaphylaxis notice something happening on the skin or in the mouth first. Watch for:

• Itching or tingling in the mouth, lips, tongue or throat
• Raised, itchy welts (hives or urticaria) anywhere on the body
• Flushing or a spreading red rash
• Swelling of the lips, eyelids, cheeks or tongue
• Itchy, watery eyes, sneezing or a suddenly runny nose

Skin signs alone do not confirm anaphylaxis — but they are a warning that a reaction is under way. Importantly, roughly one in ten people have no skin changes at all, so never wait for a rash before taking action.

Breathing and Throat: The Signs You Must Not Ignore

Any problem with the airway or breathing means this is an emergency. Call 999 and use an adrenaline auto-injector immediately if you notice:

• A tight feeling in the throat, or a sense that it is closing
• A hoarse voice, or a harsh, noisy sound when breathing in
• Swelling in the mouth or throat, or difficulty swallowing
• Wheezing, a persistent cough or tightness in the chest
• Struggling to speak in full sentences or to catch your breath

These signs can come on within seconds. If in doubt, treat it as anaphylaxis. There is no harm in giving adrenaline when it turns out not to have been needed; there is serious harm in withholding it when it was.

Circulation, Stomach and a Sense of Dread

As the reaction progresses, blood pressure can fall sharply. Look out for:

• Dizziness, light-headedness or feeling faint, especially on standing
• Pale, clammy or sweaty skin
• A rapid or pounding heartbeat
• Nausea, vomiting, stomach cramps or diarrhoea
• Confusion, agitation or a strong feeling that something terrible is about to happen

That last symptom is real and well recognised. Many people describe a sudden, overwhelming sense of doom before other signs appear. Trust it. Restlessness, a sudden need to vomit, or a feeling of impending collapse all warrant immediate treatment.

Using an Adrenaline Auto-Injector Correctly

Adrenaline is the only treatment that reverses anaphylaxis. Antihistamine tablets and inhalers may ease some symptoms but will not save a life on their own, so never rely on them first.

• Use it early. Give adrenaline at the first sign of breathing difficulty, throat swelling, or a sudden drop in blood pressure.
• Where. Inject into the outer thigh — the anterolateral aspect — through clothing if necessary. Hold the device in place for the time stated in the instructions, usually ten seconds.
• Position matters. Lie the person flat and raise their legs. Do not let them stand or sit up suddenly, as this can cause a dangerous drop in blood pressure. If breathing is difficult, they may need to sit up, but keep their legs raised if you can.
• Second dose. If there is no improvement after five minutes and you have a second device, give it.
• Call 999. Say clearly that the person is having an anaphylactic reaction and that adrenaline has been given.

After the Injection: What Happens Next

Everyone who has had adrenaline for anaphylaxis needs to be assessed in hospital, even if they seem completely recovered. A second reaction can occur hours later without further exposure to the trigger — this is known as a biphasic reaction — so observation is essential.

Between emergencies, a little preparation goes a long way. Keep two in-date auto-injectors with you at all times, check the expiry date regularly, and make sure family, friends and colleagues know where they are and how to use them. A written allergy plan, a medical ID bracelet and a short conversation with the people you spend time with can turn a frightening situation into one where everyone knows exactly what to do.