First aid for anaphylaxis

Adrenaline counteracts the dangerous effects of anaphylaxis by helping open the airways and support blood circulation. It is the priority medicine when a severe allergic reaction is suspected. Antihistamines may reduce itching or hives, while inhalers may ease some wheeze, but neither treats the full airway and circulation emergency.

Warning signs include tongue or throat swelling, hoarseness, noisy or difficult breathing, persistent cough, wheezing, faintness, confusion, or collapse after a possible allergen exposure. A rash can occur, but its absence does not make these signs less urgent.

Use the prescribed auto-injector against the outer thigh according to its instructions, then call local emergency services and say that anaphylaxis is suspected. Note when adrenaline was given. If a further prescribed dose is available and symptoms persist, follow the personal action plan or instructions from the emergency call handler.

Lay the person flat with legs raised when possible. If breathing is difficult, they may sit with legs extended and support behind them; do not let them stand or walk. Place an unconscious but breathing person on their side. If they are not breathing normally, start resuscitation if you can and use an automated external defibrillator if one is available.

Remove an ongoing trigger only when it is safe, such as stopping an injected medicine, but do not delay adrenaline to search for the cause. Do not give food or drink. Stay with the person, monitor breathing and responsiveness, and hand the used auto-injector to the ambulance team.

Every suspected anaphylactic reaction requires emergency medical assessment, even when symptoms ease after adrenaline. Breathing or circulation problems can need additional treatment, and symptoms may return after a period of improvement. Do not drive yourself if you are unwell; use emergency transport so deterioration can be managed on the way.

After the episode, request a review of the likely trigger and a written plan for future exposure. Have a clinician check your auto-injector technique and explain storage, expiry checks, replacement after use, and whether additional devices are appropriate. Make sure caregivers, teachers, travel companions, or colleagues can recognise the warning signs and locate the medicine.