What is anaphylaxis?

Anaphylaxis is a severe type of allergic reaction.

It can happen after exposure to triggers, such as:

• food — commonly milk, eggs, peanuts, tree nuts and seafood
• bites and stings — such as, bee stings, tick bites and snake bites
• some medicines

Anaphylaxis can develop quickly and can be fatal. It should be treated as a medical emergency.

If anaphylaxis progresses, it can lead to a dangerous drop in blood pressure. This is known as 'anaphylactic shock'.

What are the symptoms of anaphylaxis?

Anaphylaxis symptoms can vary, but often affect breathing, the throat and other body functions. Symptoms of anaphylaxis can include any of the following:

• difficult or noisy breathing
• difficulty talking and hoarse voice
• a swollen tongue
• persistent dizziness or collapse
• swelling or tightness in the throat
• pale and floppy (in young children)
• wheeze or persistent cough

Sometimes, mild to moderate symptoms may happen before anaphylaxis. Symptoms may include:

• swelling of face, lips and eyes
• skin changes such as hives or welts
• abdominal pain or vomiting

Watch this video from Allergy & Anaphylaxis Australia to learn how to recognise signs and symptoms of an allergic reaction.

When should I call an ambulance or go to the emergency department?

What should I do while waiting for an ambulance?

1. Lay the person flat and keep them still — do not let them stand or walk.
2. If the person is unconscious, place them in the recovery position.
3. If breathing is difficult or they are vomiting, allow them to sit with legs outstretched.
4. Use an adrenaline autoinjector, if you have not already done so.
5. If their symptoms persist 5 minutes after the first injection, you should inject another adrenaline autoinjector.

Watch this video from Allergy & Anaphylaxis Australia to see how to position a child or an adult having a severe allergic reaction.

If the person is unresponsive and not breathing normally, start CPR.

If you are not sure — always use the adrenaline autoinjector. It is better to use it than delay treating a serious reaction. Adrenaline does not have serious side effects if given unnecessarily, but can be lifesaving. If the person also has asthma, give the adrenaline autoinjector first. Then give the asthma reliever puffer.

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What causes anaphylaxis?

Anaphylaxis is triggered by the immune system when it recognises a harmless substance as 'dangerous' (allergen).

The symptoms of an allergic reaction vary from person to person. They also depend on the type of allergen and how it entered the body. It may enter the body for example through ingestion, skin contact or inhalation.

This immune response can affect many different body systems, such as your:

• skin
• digestive system
• respiratory system
• circulatory system

How is anaphylaxis diagnosed?

Anaphylaxis is diagnosed by looking at your symptoms and checking your medical history. Your doctor may also examine you to confirm the diagnosis.

Anyone who has had or may have had anaphylaxis should ask their GP for a referral to an allergy specialist. This specialist can:

• confirm the diagnosis
• give advice on avoiding future reactions
• explain what to do if another allergic reaction happens

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How is anaphylaxis treated?

Anaphylaxis requires immediate treatment with adrenaline. Treatment involves quick, supportive care and positioning. You should lie flat to help blood flow and avoid walking or standing until you are stable.

In hospital, you may also receive oxygen and fluids through a vein if needed. After treatment, you will be checked for at least 4 hours. This is to check for any return of symptoms or complications.

Follow the steps on your anaphylaxis action plan. Be aware of your position and use your adrenaline injector as directed.

What are the complications of anaphylaxis?

It is important to act quickly to help reduce your chance of complications. Untreated, anaphylaxis can quickly lead to:

• life-threatening low blood pressure (anaphylactic shock)
• breathing problems
• collapse
• death

Can anaphylaxis be prevented?

People with diagnosed allergies should avoid all triggers and confirmed allergens.

If you have an allergy, you should always carry:

• an adrenaline autoinjector (if prescribed)
• an anaphylaxis action plan

It's a good idea to ensure your friends and family know how to follow your anaphylaxis action plan in case you need help. Wearing a medical ID bracelet or necklace can also help others recognise and respond to the emergency.

Resources and support

• Australasian Society of Clinical Immunology and Allergy (ASCIA) has information on allergies and anaphylaxis, including setting up a personal action plan.
• Allergy and Anaphylaxis Australia provides information, resources and support for people living with allergies, their families and communities.
• Food Allergy Aware offers resources for people living with food allergies and those who support them.

You can also call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available 24 hours a day, 7 days a week.

Other languages

• The Australasian Society of Clinical Immunology and Allergy (ASCIA) provides information about anaphylaxis in many community languages.