Treating someone who has anaphylaxis 

If you suspect somebody is experiencing symptoms of anaphylaxis, call 999 immediately for an ambulance and tell the operator you think the person has anaphylaxis.

If you can see a potential trigger, such as a wasp or bee sting embedded in their skin, remove it.

If available, an adrenaline injection should be given as soon as a serious reaction is suspected. This can be done by the person with anaphylaxis if possible, but in some circumstances (such as cases involving a young child or someone who is unconscious) you may need to inject them yourself. 

Before attempting the injection, make sure you know the correct way to use the specific device available.

There are three types of auto-injectors:

  • EpiPen
  • Jext
  • Emerade

These auto-injectors release adrenaline when jabbed or pressed against the outer thigh.

Make sure you do not accidentally inject into a fatty part of their leg, as the adrenaline cannot move through fat. Also do not inject into a vein or artery, as this can cause dangerous side effects. The injector should only be placed firmly into the muscle of the outer thigh.

Carefully reading the manufacturer's instructions that come with the auto-injector will teach you how to do this. Make sure you read the instructions as soon as you are first prescribed an auto-injector.

After injecting, the syringe should be held in place for 5-10 seconds. Injections can be given through clothing.

Read MHRA (2014) guidelines on how to use an adrenaline auto-injector (PDF, 188Kb).

Most people should experience a rapid improvement in symptoms once the adrenaline has been used. If there is no improvement after five minutes, you should inject a second dose of adrenaline, if one is available. This should be injected into the opposite leg.

If the person has asthma and they have a reliever inhaler (usually blue), this should be used if they are wheezing.

Positioning and resuscitation

If the person is unconscious, check their airways are open and clear and also check their breathing. Then put them in the recovery position (see below) to ensure they do not choke on their vomit.

Place the person on their side, ensuring they are supported by one leg and one arm. Open the airway by tilting the head and lifting the chin.

If the person is conscious but experiencing trouble breathing, they may prefer to sit up as this will make breathing easier.

If the person is conscious but feels faint, they should lie flat with their legs elevated, if possible. They should not sit or stand as this could potentially lead to a heart attack.

If a woman is pregnant, they should lie down on their left side to avoid putting too much pressure on one of the large veins that leads to the heart.

If the person's breathing or heart stops, cardiopulmonary resuscitation (CPR) should be performed.

Admission to hospital

Even if adrenaline is given, the person will need to be admitted to hospital for observation (usually for six to 12 hours) as occasionally symptoms can return during this period.

While in hospital, an oxygen mask can be used to help breathing and you may be given fluids via an intravenous drip (directly into a vein) to help increase your blood pressure.

As well as adrenaline, additional medications such as antihistamines and corticosteroids can be used to help relieve symptoms.

Blood tests may also be carried out while you are in hospital to confirm a diagnosis of anaphylaxis.

You should be able to leave hospital when the symptoms are under control and it is felt they will not quickly return. In some cases, this may be after a few hours, but there is a chance you will have to stay in hospital for a few days if the symptoms were severe.

You may be asked to take antihistamines and corticosteroid tablets two to three days after leaving hospital to help prevent a return of symptoms.

It is likely you will be asked to attend a follow-up appointment so you can be given advice about how you can avoid further episodes of anaphylaxis. You may also be given an adrenaline auto-injector for emergency use between leaving hospital and attending the follow-up appointment. 

Read more about preventing anaphylaxis

What does adrenaline do?

Adrenaline causes the blood vessels to constrict (become narrower), which raises your blood pressure and reduces swelling. It also causes the airways to open, relieving breathing difficulties.

Symptoms of anaphylaxis

Common signs of anaphylaxis include:

  • a red, raised skin rash
  • swelling of the face, hands and feet
  • wheezing
  • feeling faint or dizzy
  • vomiting

Read more about the symptoms of anaphylaxis.

Page last reviewed: 19/12/2012

Next review due: 19/12/2014