Anaphylaxis: Meaning, Signs and Symptoms, and First Aid Treatment

What Is Anaphylaxis?

Anaphylaxis is a potentially life-threatening allergic reaction that involves multiple body systems. It is sometimes referred to as anaphylactic shock. In medical terms, anaphylaxis is studied under immunology, the branch of biology and medicine that focuses on the immune system.

According to established medical definitions, anaphylaxis is a severe, immediate, and potentially fatal systemic allergic reaction that occurs after exposure to a substance a person has previously become sensitised to. Without the prompt delivery of anaphylaxis first aid, the condition can escalate quickly and become fatal.

Understanding anaphylaxis first aid, recognising symptoms early, and acting decisively are critical to survival.

What Can Trigger Anaphylaxis?

Anaphylaxis may occur after exposure to almost any foreign substance. However, certain triggers are far more common.

Insect Bites and Stings

Venom from insect bites or stings is one of the leading causes of anaphylaxis in Australia. Common culprits include:

• Fire ants
  
• Bees
  
• Wasps
  
• Hornets

Food Triggers

Food-related allergic reactions are particularly common in children but can affect people of any age. Foods that may cause anaphylaxis include:

• Peanuts
• Fish and shellfish
  
• Milk
  
• Eggs
  
• Soy
  
• Wheat
  
• Red meat

Food Additives

Some people may experience severe allergic reactions to food additives, such as:

• Sulfites
  
• Sodium benzoate
  
• Food colourings

Medications

Certain medications are known to trigger anaphylaxis, including:

• Non-steroidal anti-inflammatory drugs (NSAIDs)
  
• Beta-lactam and non-beta-lactam antibiotics
  
• Radiocontrast media (RCM)
  
• Proton pump inhibitors (PPIs)
  
• Neuromuscular blocking agents (NMBAs)
  
• Sugammadex
  
• Hypnotics
  
• Opioids
  
• Chlorhexidine
  
• Dyes and colloids

Latex

Latex exposure, particularly in medical or workplace settings, can cause severe allergic reactions in sensitised individuals.

Who Is More Likely to Experience Anaphylaxis in Australia?

Anaphylaxis can affect anyone, regardless of age or background. However, it may be more common among:

• Older adults
  
• People with asthma or other breathing problems
  
• Individuals with existing allergic conditions
  
• People with chronic skin conditions

Australia has one of the highest recorded rates of fatal anaphylaxis compared to other developed countries. Between 1997 and 2013, the Australian Bureau of Statistics recorded 324 deaths caused by anaphylaxis, highlighting the importance of public awareness and first aid education.

Recognising the Signs and Symptoms of Anaphylaxis

The signs and symptoms of anaphylaxis may appear within minutes or up to several hours after exposure to an allergen. Symptoms can progress rapidly and should never be ignored.

Skin and Mucosal Symptoms

• Hives
  
• Itching
  
• Flushed or pale skin
  
• Swelling of the lips, face, tongue, or throat

Respiratory Indicators

• Wheezing
  
• Shortness of breath
  
• Tightness in the chest
  
• Difficulty breathing or swallowing

Cardiovascular and Gastrointestinal Warning Signs

• Low blood pressure
  
• Weak or rapid pulse
  
• Dizziness or fainting
  
• Nausea
  
• Vomiting
  
• Diarrhoea

These symptoms together indicate anaphylactic shock, which is a medical emergency requiring immediate allergic reaction treatment.

Immediate Anaphylaxis First Aid Steps

Step 1 – Call Emergency Services

Dial Triple Zero (000) immediately if anaphylaxis is suspected. Even if symptoms appear mild at first, they can worsen quickly.

Step 2 – Administer an Epinephrine Auto-Injector

A person experiencing anaphylaxis should be injected with epinephrine (adrenaline) without delay. Epinephrine is the most effective treatment for reversing the life-threatening symptoms of anaphylaxis.

Step 3 – Positioning and Monitoring

• Lay the person flat if possible
  
• Do not allow them to stand or walk
  
• If breathing is difficult, they may sit upright
  
• Monitor breathing and responsiveness until help arrives

What You Should Know About Epinephrine and EpiPens

What Is Epinephrine?

Epinephrine, also known as adrenaline, is a hormone and neurotransmitter produced by the adrenal glands. When administered during anaphylaxis, it:

• Relaxes airway muscles
  
• Tightens blood vessels
  
• Improves blood pressure and heart function

How Is Epinephrine Given?

Epinephrine injections are available in vials and pre-filled auto-injectors, such as the EpiPen. These devices deliver medication into the muscle or just under the skin.

How to Use an EpiPen Correctly

Knowing how to use an EpiPen correctly is a vital part of anaphylaxis first aid:

• Inject into the middle of the outer thigh
  
• Never inject into veins, buttocks, fingers, toes, hands, or feet
  
• Seek medical help immediately after use

If used on children, their leg should be held firmly to prevent movement and reduce the risk of injury.

Choosing the Right Dose

Prescribed EpiPen doses are based on body weight:

• 30 kg (66 lbs) or more: EpiPen 0.3 mg
  
• 15–30 kg (33–66 lbs): EpiPen Jr 0.15 mg

When to Give a Second Dose

Two EpiPens are commonly prescribed for a single anaphylactic episode. A second dose may be given if symptoms persist, but additional doses should only be provided by healthcare professionals.

Side Effects and Safety Considerations

In rare cases, infection may develop at the injection site within a few days. Seek medical advice if there is:

• Persistent redness
  
• Swelling
  
• Tenderness
  
• Warmth at the injection site

Possible side effects of epinephrine include:

• Anxiety or restlessness
  
• Tremor or weakness
  
• Dizziness
  
• Sweating
  
• Palpitations
  
• Nausea or vomiting
  
• Headache
  
• Breathing difficulties

Immediate medical care is required if adverse reactions occur.

Follow-Up Care and Emergency Response

After any anaphylactic reaction, hospital observation is essential. Symptoms can return hours later in what is known as a biphasic reaction. Medical professionals may monitor the individual and adjust ongoing allergy management plans.

Wearing medical identification and having an updated allergy action plan can significantly reduce future risks.

Prevention, Education, and Preparedness

Avoiding Common Triggers

Identifying and avoiding known allergens is a key preventive strategy. This may involve reading food labels carefully, informing schools and workplaces, and carrying prescribed auto-injectors at all times.

School and Workplace Preparedness

Australian schools and many workplaces implement anaphylaxis management policies to protect individuals with known allergies. Education and preparedness can save lives.

First Aid and CPR Training in Australia

Correct use of an EpiPen auto-injector can be challenging without training. First aid courses in Australia teach:

• Anaphylaxis first aid and allergic reaction treatment
  
• EpiPen steps and administration
  
• CPR and emergency response
  
• Asthma management
  
• Bandaging and recovery positioning

CPR First Aid courses offer these essential skills. They include HLTAID011 Provide First Aid and HLTAID009 Provide Cardiopulmonary Resuscitation.  

Conclusion

Anaphylaxis is a medical emergency that requires immediate recognition and action. Effective anaphylaxis first aid involves identifying symptoms early, administering epinephrine promptly, and seeking emergency medical assistance. Education through accredited first aid training in Australia equips individuals with the confidence and skills needed to respond correctly, not only to anaphylaxis but to many other life-threatening emergencies. Proper preparation saves lives.