Anaphylaxis

About anaphylaxis

Anaphylaxis is a severe allergic reaction and requires immediate medical attention. Within minutes of exposure to the allergen, or ‘trigger’, a person can have potentially life-threatening symptoms such as breathing and/or heart symptoms.

There is currently no cure for allergy.

The best way to prevent anaphylaxis is to avoid whatever causes the allergic reaction. When accidental exposure occurs follow instructions on your Australasian Society of Clinical Immunology and Allergy Action Plan for Anaphylaxis (ASCIA Action Plan).

People at risk of anaphylaxis must always carry their ASCIA Action Plan and their adrenaline injector (EpiPen® or Anapen®) with them at all times.

If you are thought to be at risk of anaphylaxis or you have anaphylaxis for the first time, your doctor will refer you to a clinical immunology/allergy specialist, who will make a diagnosis and provide advice on preventative management and emergency treatment.

Anaphylaxis is a severe allergic reaction

Allergy occurs when the immune system overreacts to a substance or ‘trigger’ in the environment that is harmless for most people. The trigger is called an allergen. The immune system responds by making an antibody to attack the allergen and this starts off a range of immune system reactions.

Allergies can be mild, moderate or severe.

Anaphylaxis is the most severe type of allergic reaction. Hospital admissions for anaphylaxis have increased five-fold in the last 20 years and anaphylaxis from food allergy reactions has doubled in the last 10 years.

Signs and symptoms of anaphylaxis

Anaphylaxis can occur within minutes. It mostly occurs within 20 minutes to 2 hours after exposure to the allergen.

Signs and symptoms may be mild at first, but can get worse very quickly. A small number of people suddenly develop signs and symptoms of a severe allergic reaction (anaphylaxis) without any signs of a mild to moderate allergic reaction.

Signs of a mild to moderate allergic reaction include:

• swelling of lips, face, eyes
• hives or welts appearing on the skin
• tingling mouth
• abdominal pain, vomiting (these are signs of anaphylaxis for insect allergy).

Signs of a severe reaction (anaphylaxis) include:

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

Triggers for anaphylaxis

Some of the more common triggers (allergens) that can lead to anaphylaxis include:

• food – any food can be a trigger. However, the foods that account for about 90% of allergic reactions are shellfish, fish, eggs, milk, wheat, peanuts, tree nuts, sesame and soy
• insect bites and stings – including bees, wasps, jack jumper ants, green ants and fire ants. Ticks (arachnids) can also trigger anaphylaxis
• medicines – some prescription drugs (such as penicillin), over-the-counter medicines (such as aspirin) and herbal preparations.

Less common triggers include exercise, anaesthetic drugs and latex.

Sometimes, despite many investigations, a person’s trigger allergen/s cannot be identified. These are referred to as ‘unknown triggers’.

Risk factors for anaphylaxis

There are a number of factors that appear to increase the risk and/or severity of anaphylaxis at the time of exposure to the allergen/trigger. These include:

• poorly controlled asthma
• exercise
• alcohol
• fatigue (tiredness)
• posture – standing and walking
• hormonal changes (for example, in women that are premenstrual or menstrual)
• amount of food eaten and how it is prepared (in people with food allergy)
• taking a non-steroidal anti-inflammatory medication such as aspirin or ibuprofen.

Diagnosis of allergy

If you are thought to have a moderate/severe allergy or you experience anaphylaxis for the first time, your general practitioner (GP) will:

• record the history of your allergic reaction and suspected trigger/s
• refer you to a clinical immunology/allergy specialist
• inform you about patient support services, such as Allergy & Anaphylaxis Australia.

A GP cannot provide an individual with an initial authority prescription for an adrenaline injector (EpiPen® or Anapen®) unless this is done in consultation with a clinical allergy/immunology specialist.

In order to make a diagnosis, the clinical immunology/allergy specialist will:

• Take a medical history including detailed questioning about what led up to the event.
• Perform a physical examination.
• Perform investigations. These could be:
  • blood tests to measure allergen specific antibodies, known as immunoglobulin E (IgE)
  • skin prick tests to confirm or rule out suspected triggers
  • tests to exclude other medical conditions that can look like an allergic reaction or anaphylaxis.

Some ‘allergy tests’ are not proven

Some ‘tests’ that claim to diagnose allergies are not scientifically or medically proven.

Tests that are not proven to provide accurate information on your trigger/s for allergic reactions, including anaphylaxis, can be dangerous. Relying on an unproven test may mean you don’t get the medical attention you need. It may also delay you receiving a diagnosis and anaphylaxis management advice. It can be expensive and also result in unnecessary dietary and lifestyle restrictions.

Some alternative testing methods that may lead to inappropriate or inadequate treatment include:

• Alcat testing
• allergen elimination techniques
• cytotoxic food testing
• kinesiology
• hair or stool analysis
• IgG antibody testing to food
• iridology
• pulse testing
• reflexology
• Rinkel’s intradermal testing
• Vega testing.

Management of allergy

Your clinical immunology/allergy specialist will discuss:

• how to prevent an allergic reaction. For food allergy, advice from an experienced food allergy dietitian may also be needed
• how to manage an allergic reaction. This includes completing an ASCIA Action Plan for Anaphylaxis/Allergic reactions that outlines emergency management and providing education on how to use an adrenaline injector if prescribed.

Your clinical immunology/allergy specialist may prescribe an adrenaline injector). Not everyone with a food, insect or other allergy will be prescribed an adrenaline injector. The specialist will assess level of risk. Those with medication allergy are generally not prescribed an adrenaline injector as the trigger is easier to avoid compared to food or insect allergy.

You will need regular follow-up visits with a clinical immunology/allergy specialist.

Treatment for anaphylaxis

Anaphylaxis is a medical emergency.

Emergency treatment includes following instructions on your individual ASCIA Action Plan for Anaphylaxis or First Aid Plan for Anaphylaxis.

1. Lay the person flat (do not allow them to stand or walk).
2. Give adrenaline injector.
3. Phone ambulance – dial triple zero (000).
4. Phone family/emergency contact.
5. Further adrenaline doses may be given if no response after 5 minutes.
6. Transfer person to hospital for at least 4 hours of observation.

Always give adrenaline injector first, and then asthma reliever puffer if someone with known asthma and severe allergy to food, insect or medication has sudden breathing difficulty, even if no skin signs (hives or welts) are present.

Commence CPR at any time if the person is unresponsive and not breathing normally.

Adrenaline injectors

Adrenaline is the first line treatment for anaphylaxis. Adrenaline is injected into the muscle of the outer mid-thigh (that is, midway between the knee and hip joints on the outer side of the thigh) using an adrenaline injector.

Once you are diagnosed at risk of anaphylaxis, it is important to always carry your adrenaline injector/s and your ASCIA Action Plan, which is completed and signed by your doctor or nurse practitioner.

In Australia, the devices currently available are EpiPen® and Anapen®. They are prescribed on an ‘authority prescription’, allowing people to get 2 government-subsidised devices (on the Pharmaceutical Benefits Scheme (PBS)). They are also available over the counter at the pharmacy at full cost.

The adrenaline injectors are designed to deliver a single pre-measured dose of adrenaline.

EpiPen® comes in 2 doses:

• EpiPen® for children over 20kg and adults
• EpiPen® Jnr for children who weigh between 7.5kg and 20kg.

Anapen® comes in 3 doses:

• Anapen® 500 for children and adults over 50kg
• Anapen® 300 for children over 20kg and adults
• Anapen® 150(Jr) for children who weigh between 7.5kg and 20kg.
  

You will be given detailed instructions on how to use your adrenaline injector from your treating doctor or pharmacist. ASCIA has information on adrenaline injectors and frequently asked questions.

You can also visit Allergy & Anaphylaxis Australia to view videos on signs and symptoms, how to position a child/adult during anaphylaxis and how to use an EpiPen® and Anapen®.

Prevention of anaphylaxis

The best way to avoid anaphylaxis is to:

• avoid triggers – the most important management strategy is to avoid all known triggers (allergens)
• if you have a food allergy, always read food labels and tell staff about your allergy when eating out
• if you have an insect allergy, always be aware of environments that may increase the risk of insect sting or bite, and do what you can to minimise exposure.

Other recommendations include:

• Complete the free, online ASCIA Anaphylaxis e-training for first aid (community).
• Tell people about your allergy:
  • Let your workplace know about your allergy, and make a few work colleagues aware of where your emergency medication is kept, and how to administer it to you.
  • If you have a medication allergy, be sure to always tell every treating doctor and pharmacist about your allergy.
  • Wear a medical identification bracelet – if you lose consciousness, your medical identification bracelet will alert ambulance officers or hospital staff of your condition.
• If you are finding your food allergy difficult to manage, or if you have multiple food allergies, consider making an appointment with a specialised food allergy dietitian.
• Take extra precautions when eating out if you have a food allergy.
• Take extra precautions when travelling with allergy.
• Seek information and support from Allergy & Anaphylaxis Australia - an evidence-based organisation with information, resources and support from trained allergy educators.

Children with severe allergies

Suggestions for parents of children with severe allergies include:

• Educate your child, taking their age and level of understanding into account. If your child has food allergy, stress the importance of only accepting food from trusted adults such as parents or caregivers, never sharing food and washing hands before and after eating.
• Advise the childcare service, kindergarten, school and other carers of your child’s severe allergy.
• Give the organisation a current copy of your child’s ASCIA Action Plan, which includes a recent photograph of your child.
• Make sure you provide at least one in-date adrenaline injector.
• Work with your child’s school or childcare setting to implement a management plan to reduce the risk of allergic reactions, including anaphylaxis. Allergy Aware’s Best Practice Guidelines and resources have been developed to guide schools and early children’s education and care services on anaphylaxis prevention and management.

Long-term outlook for allergy

Most children grow out of allergies to milk, egg, wheat and soy. However, allergies to peanut, tree nuts, sesame and seafood are usually lifelong.

People that have had anaphylaxis because of insect allergy should discuss with their clinical immunology/allergy specialist if immunotherapy (desensitisation) is available and suitable for them.

Anaphylaxis training

Anaphylaxis training options include:

• ASCIA Anaphylaxis e-training for first aid (community) – this is online training for members of the community, such as parents, friends, carers, workplace colleagues, students and club members.
• ASCIA Anaphylaxis e-training for schools and children’s education/care.
• Food allergy training – free, online food allergen management training developed by the National Allergy Council (NAC) that includes courses for food business staff, cooks and chefs, schools, children’s education and care, camps, hospitals and residential care.

Where to get help

• In an emergency, always call triple zero (000)
• Your GP (doctor)
• Allergy & Anaphylaxis Australia (A&AA) Tel. 1300 728 000
• Anaphylaxis Support Advisory Line (Royal Children’s Hospital Melbourne) Tel. 1300 725 911
• Australasian Society of Clinical Immunology and Allergy (ASCIA)
• Dietitians Australia Tel. 1800 812 942