An anaphylaxis emergency is a severe, potentially life-threatening allergic reaction that requires immediate emergency treatment. Unlike mild to moderate allergic reactions, anaphylaxis affects multiple body systems simultaneously, developing rapidly after exposure to an allergen. The Australasian Society of Clinical Immunology and Allergy (ASCIA) defines anaphylaxis as a severe allergic reaction characterised by respiratory or cardiovascular symptoms, often accompanied by skin symptoms and gastrointestinal symptoms.
In Australia and New Zealand, anaphylaxis affects approximately 1 in 50 people at some point in their lifetime. Understanding the difference between a mild allergic reaction and acute anaphylaxis is critical for proper recognition and treatment. For individuals with known asthma and allergy to food or other triggers, the risk of anaphylaxis is significantly higher, with asthma being a key risk factor for fatal anaphylaxis.
Signs and Symptoms of Anaphylaxis
Recognising anaphylaxis symptoms quickly can be life-saving. According to ASCIA guidelines, anaphylaxis emergency is a medical emergency characterised by:
- Sudden breathing difficulty, wheeze or persistent cough
- Swelling of tongue, throat or lips
- Difficulty talking or hoarse voice
- Drop in blood pressure causing dizziness/collapse
- Pale and floppy (especially in young children)
These symptoms often occur alongside skin symptoms such as hives, swelling, and itching. However, the National Allergy Council emphasises that anaphylaxis can occur without skin symptoms in up to 20% of cases. This is why health professionals focus on respiratory or cardiovascular symptoms as the primary indicators of anaphylaxis.
The type of allergic reaction and its severity can vary between individuals. For someone with known asthma experiencing anaphylaxis, symptoms may initially resemble an asthma attack but will not respond to standard asthma treatment.
First Aid for a Severe Allergic Reaction
When someone is experiencing an anaphylaxis emergency, follow this emergency response protocol:
- Lay the person flat – do not allow them to stand or walk. If breathing is difficult, allow them to sit but not stand.
- Give adrenaline – use an adrenaline autoinjector (such as EpiPen) if available. Adrenaline is the first line treatment for anaphylaxis.
- Call emergency services (Triple Zero/000) – state clearly that the person is experiencing anaphylaxis.
- Further adrenaline doses may be given after 5 minutes if no improvement.
- If unconscious, place in recovery position and ensure airway is clear.
ASCIA emphasises that adrenaline (also known as epinephrine) is the only effective treatment for anaphylaxis. Antihistamines do not treat the life-threatening cardiovascular symptoms of anaphylaxis and should never delay the administration of adrenaline.
The Department of Health and the Australasian Society of Clinical Immunology and Allergy strongly advise against waiting to see if symptoms will improve on their own. Delay in giving adrenaline is associated with fatal anaphylaxis.
Epinephrine Auto-Injectors
Adrenaline autoinjectors are pre-filled devices designed for the emergency treatment of anaphylaxis emergency. In Australia, the most common brand is EpiPen, though other options may be available.
To use an adrenaline injector correctly:
- Form a fist around the device with the orange end pointing downward
- Remove the blue safety cap by pulling straight up
- Place the orange end against the outer mid-thigh (with or without clothing)
- Push down firmly until a click is heard and hold for 3 seconds
- Remove and massage injection site for 10 seconds
According to ASCIA anaphylaxis e-training, common mistakes include:
- Not holding the injector in place for the full 3 seconds
- Placing the thumb over the end of the device
- Injecting into buttocks or veins (always use outer mid-thigh)
- Testing or firing the device before use (each device can only be used once)
For those prescribed an adrenaline injector by an allergy specialist, carrying it at all times is essential for preparing for an emergency. The dose of adrenaline in autoinjectors is calculated based on weight, with junior doses available for young children.
After Administration: Next Critical Steps
After giving adrenaline, the acute management of anaphylaxis emergency continues:
- Monitor continuously – Watch for improvement or deterioration
- Prepare for a second dose – Approximately 1 in 5 people experiencing anaphylaxis require a second dose of adrenaline
- Provide clear information to emergency services upon arrival, including:
- Time of allergen exposure
- Symptoms observed
- Time adrenaline was administered
- Any known asthma and allergy history
- Any other treatment provided
Even if symptoms improve after adrenaline, the person must be transported to an emergency department for observation. This is because biphasic reactions (a second wave of symptoms) can occur hours after the initial reaction. According to the Emergency Care Institute website, observation for at least 4-6 hours is standard practice in the acute management of anaphylaxis.
If the person has known asthma, inform the paramedics as this may influence their treatment options.
Preparing for an Emergency by Creating an Action Plan
An ASCIA Action Plan for Anaphylaxis is a personalised first aid plan prescribed by a doctor. This document outlines:
- Person’s name and photo
- Known allergens
- Signs of mild to moderate allergic reactions versus anaphylaxis emergency
- Emergency contact details
- Clear instructions for first aid management of anaphylaxis
Every individual at risk of anaphylaxis should have an ASCIA Action Plan that is regularly updated by their doctor. The Society of Australia and New Zealand recommends these plans be distributed to all relevant settings including:
- Schools and childcare
- Workplaces
- Sports clubs
- Family members’ homes
ASCIA first aid plans are colour-coded for easy identification: red for autoinjector plans and green for general action plans. These plans should be displayed in prominent locations and included with emergency medication.
Anaphylaxis Australia recommends regular practice drills to ensure everyone responsible for the person knows how to implement the action plan for anaphylaxis efficiently during an emergency.
Prevention Strategies
While treatment with epinephrine is crucial during an emergency, prevention remains the cornerstone of managing risk of anaphylaxis. Effective prevention strategies include:
- Allergen identification and avoidance – Work with an allergy specialist for proper diagnosis of anaphylaxis emergency triggers
- Medical alert identification – Wear a bracelet/necklace that identifies your allergy
- Education – Ensure family, friends, and colleagues understand recognition and treatment of anaphylaxis
- Regular medical reviews – Visit your clinical immunology and allergy specialist annually to review your action plan for anaphylaxis
- Management of asthma – For those with known asthma, maintaining good asthma control reduces risk factors for fatal anaphylaxis
The National Allergy Council provides comprehensive resources about risk factors for fatal anaphylaxis and strategies to minimise these risks. They emphasise that the most dangerous scenarios involve delays in recognition and treatment, particularly in individuals with known asthma.
Remember that anaphylaxis is a severe, life-threatening allergic reaction requiring immediate action. By understanding the signs, having appropriate medication, following your ASCIA action plan, and seeking emergency treatment promptly, the risk of serious outcomes can be significantly reduced.
Frequently Asked Questions
Can I use someone else's adrenaline autoinjector in an emergency?
Yes. ASCIA guidelines support using another person’s adrenaline autoinjector during anaphylaxis emergency when the person doesn’t have their own. Adrenaline is the first line treatment for this life-threatening allergic reaction, and benefits outweigh risks. Even if only an adult-dose is available for a small child, health professionals recommend using it rather than leaving anaphylaxis untreated.
Can antihistamines prevent anaphylaxis if taken quickly?
No. Antihistamines cannot prevent or treat anaphylaxis emergency. They only relieve mild allergy symptoms and have no effect on the dangerous respiratory or cardiovascular symptoms that characterise severe allergic reactions. Antihistamines work too slowly and don’t address breathing difficulties or drop in blood pressure. Only adrenaline effectively treats anaphylaxis.
How does asthma affect anaphylaxis risk?
Known asthma significantly increases anaphylaxis risk and severity. Many fatal anaphylaxis cases occur in people with asthma. Respiratory symptoms may initially resemble an asthma attack but won’t respond to standard asthma treatments. Good asthma control reduces risk factors for fatal anaphylaxis. During an anaphylaxis emergency, adrenaline remains the first line treatment for someone with both conditions.
