What is anaphylaxis?
Anaphylaxis (an-a-fi-LAK-sis) is a severe allergic reaction that is rapid in onset and can be life-threatening. The most common anaphylactic reactions are to foods, insect stings, medications and latex. Anaphylaxis is the most severe form of allergic reaction, often affecting several parts of the body, including either breathing difficulties, a sudden drop in blood pressure, or both.
Mild symptoms can progress rapidly to a severe reaction. Anaphylaxis must be treated as a medical emergency requiring immediate medical attention. Prompt treatment with injected adrenaline is required to halt the progression of the reaction.1
Certain people are more at risk of anaphylaxis. If you have allergies or asthma and have a family history of anaphylaxis, your risk is higher. And, if you’ve experienced anaphylaxis your risk of having another anaphylactic reaction is increased.
Who is at risk of anaphylaxis?
Anyone with an allergy to any substance is at risk of anaphylaxis.
While anaphylactic reactions remain relatively rare, we currently have no way of knowing if a person who previously has experienced only mild or moderate symptoms when exposed to a trigger, will at some time in the future develop more severe or life-threatening symptoms.
Allergies cannot be cured, and children may not ‘grow out of them’. But you can reduce the risks associated with severe allergies by avoiding your triggers and being prepared.
Why does anaphylaxis occur?
If you are allergic to a substance, your immune system overreacts to this allergen by releasing chemicals that cause allergy symptoms. Typically, these bothersome symptoms occur in one location of the body. However, some people are susceptible to a much more serious anaphylactic reaction. This reaction typically affects more than one part of the body at the same time.
The function of the immune system is to protect the body from foreign invaders. In people with severe allergies or anaphylaxis, the immune system ‘overreacts’ to the allergen. Contact with, or ingestion of this allergen sets off a chain reaction in a person’s immune system that may lead to anaphylaxis. Several factors can influence the severity of allergic reaction. These include exercise, heat, alcohol, and in food allergic people, the amount eaten, and how it is prepared.2
Signs and symptoms
It is important to know the warning signs and symptoms of anaphylaxis
Sometimes, before an anaphylactic reaction occurs, a person experiences mild symptoms. These may include tingling of the skin, hives or welts, swelling of face, lips and/or eyes, and nausea. These early symptoms can be a useful warning that exposure to a trigger has occurred, and that treatment may be needed.
Not everyone affected by anaphylaxis will experience the same thing, but common symptoms of anaphylaxis that are potentially life-threatening include the following: 3
- Difficult/noisy breathing
- Swelling of the lips and/or tongue
- Swelling/tightness in throat
- Difficulty talking and/or hoarse voice
- Wheeze or persistent cough
- Persistent dizziness and/or collapse
- Pale and floppy (in young children)
- Low blood pressure.
Symptoms you should look for:
Swelling, tightness or closure
Weak pulse, dizziness or unconciousness
Coughing, wheezing difficult or noisy breathing
What should you be aware of?
SEVERE ALLERGIC RHINITIS
(symptoms include sneezing and itchy, watery nose and/or eyes)
How quickly do symptoms appear?
The signs and symptoms of anaphylaxis usually occur within the first 20 minutes to 2 hours after exposure.
Rapid onset and development of potentially life-threatening symptoms are characteristic markers of anaphylaxis. Allergic symptoms may initially appear mild or moderate but can progress rapidly. The most severe reactions involved the respiratory system (breathing) and/or cardiovascular system (heart and blood pressure).1
Know the difference between a mild, moderate, or severe reaction.
Allergic reactions can be mild, moderate or severe. Most allergic reactions have mild to moderate symptoms, generally involving just one part of the body. For example, if you have a food allergy you probably experience gastrointestinal symptoms; and if you are allergic to something like latex your skin is most likely to show the results when you touch it. However, if you have a severe allergic reaction, different parts of the body can be affected at the same time.
For example, a mild allergic reaction to a food trigger might be tingling of the lips, whereas a severe reaction would be swelling of the tongue. A moderate allergic reaction to an insect sting could be itching, reddening, swelling and pain around the area the sting occurred, whereas a severe reaction might involve a widespread rash, dizziness and difficulty breathing.
What causes anaphylaxis?
Anaphylaxis can be triggered by a number of allergens including:
Asthma and Anaphylaxis 5
Asthma is a chronic inflammatory disease of the airways. People with asthma experience a narrowing of the airways due to inflammation in the lungs, which blocks the flow of air into and out of the lungs. Asthma is most easily recognised by the following symptoms:
- Wheezing (noise when breathing out).
- Persistent cough, especially at night.
- Difficulty breathing and shortness of breath.
- Tightness and heaviness in the chest.
- Wheezing or coughing with exercise (exercise induced asthma).
Symptoms such as wheezing, difficulty breathing and persistent cough can also present with anaphylaxis and sometimes you may be unsure if it is asthma or anaphylaxis.
Asthma, food allergy and high risk of anaphylaxis (severe allergic reaction) frequently occur together. This increased risk of anaphylaxis in asthmatic individuals highlights the importance of managing your asthma well as part of your anaphylaxis risk management.
If you have sudden onset of breathing difficulty soon after an insect sting or exposure to food or medication you may be experiencing anaphylaxis, not just asthma. It is important to note that;
- The progression and severity of allergic reactions can be unpredictable.
- Most food related allergic reactions start within 20 minutes or up to 2 hours after exposure.
- Mild to moderate symptoms of allergy may or may not present before symptoms of anaphylaxis.
If you are unsure if you are experiencing anaphylaxis or asthma, always give adrenaline auto-injector first, then asthma reliever puffer. Refer to the ASCIA Action Plan for Anaphylaxis here for step by step instructions.
How is anaphylaxis treated?
Acting fast is important
If you, your child or someone you’re caring for is experiencing anaphylaxis, administer EpiPen® or EpiPen® Jr Auto-Injector immediately. The adrenaline within EpiPen® helps to allieviate the life threatening symptoms of anaphylaxis, allowing time to seek emergency medical care.
According to Allergy & Anaphylaxis Australia, research has shown that fatalities more often occur away from home and are associated with either not using, or a delay in using, adrenaline treatment. That’s why it is so important to be prepared by carrying your EpiPen® Auto-Injector at all times.7
Adrenaline is the first-line treatment for anaphylaxis
Adrenaline works rapidly to reverse the effects of anaphylaxis and is the first line treatment for anaphylaxis. Adrenaline auto-injectors contain a single, fixed dose of adrenaline, and have been designed to be easily self-administered in two simple steps.
Antihistamines do not treat the life-threatening symptoms of anaphylaxis and are therefore not a recommended treatment for anaphylaxis.
Up to 1 in 5 anaphylactic reactions are biphasic
If the initial response to using your EpiPen® Auto-injector is not resolving the situation quickly or if the attack is severe, a second EpiPen® Auto-injector can be used after 5-15 minutes. It is also useful to understand that up to 1 in 5 people may need additional adrenaline doses due to what’s known as a biphasic reaction or continuing symptoms. 1,6,8
For this reason, it is important that people at risk for anaphylaxis ideally always have two doses of adrenaline (two EpiPen’s) available at all times.
Always be prepared
Be careful to identify and avoid triggers
Knowing and avoiding your specific triggers is the most important part of managing life-threatening allergies. But to do that, you need to know what to avoid, and where that substance might
If you are at risk of anaphylaxis it is very important that your family, friends and work colleagues, or your child’s teachers also know; and that they know what to do if you do have an anaphylactic reaction. You and your doctor may decide you should carry an adrenaline auto-injector, so you can receive immediate treatment if you experience an anaphylactic reaction. EpiPen® Auto-Injectors are available from your pharmacy without a prescription.
Always carry two EpiPen®s
Because up to 1 in 5 people may need additional adrenaline doses due to what’s known as a biphasic reaction or continuing symptoms, it is wise to always carry two EpiPen’s with you at
Know how to respond if symptoms occur
Avoiding triggers is not always easy, because they are not always obvious. For example, a person with a severe peanut allergy might not realise that the chocolate cake they are about to eat contains traces of peanuts. Always ask about food ingredients if you are not sure, and if in doubt, just don’t eat it. Accidental exposure to a trigger is always a risk no matter how carefully prepared you are.
Knowing what to do if you, or a person you care for, have a severe allergic reaction can be a life-saving skill. It is recommended that everyone who has a confirmed allergy should have an Action Plan for Anaphylaxis.
1. Lieberman P, Nicklas RA, Oppenheimer J, et al. The diagnosis and management of anaphylaxis practice parameter: 2010 update. J Allergy Clin Immunol. 2010; 126(3):477-480.e1-42.
2. ASCIA – Information for patients, consumers and carers: «Anaphylaxis», 2015. Available at www.allergy.org.au/patients/information. Accessed April 2019.
3. Simons FE. Anaphylaxis. J Allergy Clin Immunol. 2010; 125(2)(suppl 2):S161-S181.
5. Australasian Society of Clinical Immunology and Allergy (ASCIA). Asthma and Anaphylaxis. Available at: www.allergy.org.au Accessed April 2019.
6. Simons FE, et al. World allergy organization guidelines for the assessment and management of anaphylaxis. World Allergy Organ J. 2011;4(2):13-37.
7. Allergy & Anaphylaxis Australia (AAA). What is Anaphylaxis? Available at: www.allergyfacts.org.au.
8. Boyce JA, et al. Guidelines for the Diagnosis and Management of Food Allergy in the United States. J Allergy Clin Immunol. 2010 Dec; 126(6 0): S1–S58.