What is an allergy?

Allergy occurs when your immune system reacts to (what should be) harmless external substances, for instance pollen, bee venom, dust mites and medications.

These substances are called allergens and the reactions can vary from mild to life-threatening (anaphylaxis).

Allergen Exposure
When exposure to an allergen has occurred, the antibody response system in your body is triggered.

Antibodies attach to specialised cells called mast cells and basophils, these cells release several substances including histamine.

These substances cause swelling and inflammation and can cause great discomfort including itchy and runny nose, eyes and throat (hay fever/allergic rhinitis), asthma exacerbation and breathing difficulties, eczema, and hives.

Allergy Symptom Development

Some people don’t develop symptoms of allergy until their teens or later. People who emigrate from one country to another may have no symptoms for several years and then develop allergic disorders.

How prevalent are allergies in Australia?

  • Allergic Rhinitis and Hay Fever affects 15% – 20% of Australians.

  • Food Allergy affects up to 8% of children under the age of five and 2% of adults.

  • Atopic Dermatitis or Eczema  affects approximately 5-20% children worldwide.
    It is often intensely itchy, resulting in chronic scratching and can be complicated by secondary infection.
    Allergens such as dust mites and certain foods (such as eggs, cow’s milk, wheat, soya bean, peanut and shellfish) may aggravate AD in some patients, but are rarely the main underlying cause.

Allergy – Intolerance – Sensitivity

  • An allergy occurs when the body’s immune system inappropriately reacts to proteins external to the body, including food or substances like pollen, pet dander, bee venom and medication.

  • A food intolerance is not based on an immune response and doesn’t show up on allergy tests. Symptoms can include headaches and gut symptoms.

  • Food sensitivity is a non-specific term used instead of intolerance or allergy.

  • Coeliac disease is not an allergy or intolerance, it is an autoimmune disease where the immune system reacts abnormally to the protein gluten and attacks and damages the lining of the bowel.

  • Itching, burning or swelling around the mouth
  • Runny nose, sneezing, nasal stuffiness
  • Watery, itchy eyes
  • Breathing difficulties, including wheezing, coughing and asthma
  • Abdominal cramps, vomiting and diarrhoea
  • Hives, eczema
  • Swelling of the tongue and throat
  • Dizziness or loss of consciousness
  • Mouth ulcers
  • Asthma-like symptoms
  • Sinus problems
  • Headache, migraine
  • Nausea, abdominal pains/bloating and bowel irritability
  • Flushing
  • Chronic fatigue and general feeling of being run down
  • Irritability and restlessness (more common in children)

Common Food Intolerances

  • Lactose A sugar found in milk which can causes gut symptoms such as bloating, pain and diarrhoea

  • Amines  Found in some fruit, vegetables, wine, chocolate and cheese.

    Chemicals in these foods cause blood vessels to expand, resulting in flushing, congestion and migraines.

  • Sulfites A type of preservative used in drinks and dried fruit. Can cause wheezing and other respiratory symptoms.

  • Salicylates Aspirin-like compounds found in some herbs, spices, fruits and vegetables. Can cause a range of symptoms including asthma-like symptoms, congestion and headache.

  • Glutamates (MSG) Found in camembert, parmesan cheese, tomatoes, soy sauce and mushrooms.  Symptoms may include headache, hives, nasal congestion or runny nose.

  • Gluten Gluten intolerance is associated with gut symptoms such as bloating, diarrhoea and nausea, as well as fatigue and psychological symptoms such as depression and brain fog.

  • FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols) – A diet low in FODMAPs can resolve irritable bowel syndrome (IBS) symptoms in many people. A low-FODMAP diet usually reduces the amount of grains, fruits and vegetables, dairy and legumes that you eat. This type of diet should be done under the supervision of a dietitian to avoid nutritional deficiencies.