Decades ago, food allergies were relatively rare. Today allergies are among the fastest-growing conditions in Australia, according to the Australasian Society of Clinical Immunology and Allergy (ASCIA). Approximately 20 per cent of Australians have an allergic disease with 10 per cent of infants experiencing immediate food allergies. Food allergies and eczema are more common in children. Insect allergy, drug allergy, asthma and allergic rhinitis (or hay fever) are more prevalent in older people.

Allergens are substances that provoke allergies. Potential allergens are everywhere — in the air, animals, food, drink, cleaning agents, personal care products, insect stings, medicines, plants, metals, latex and agricultural products. Studies show that while we can outgrow allergies to cow’s milk, egg, soy or wheat, approximately 75 per cent of children have persistent allergies to nuts, sesame and seafood. The mechanism of allergies is clear but their cause and cure remains hazy.

Allergies explained

There are two types of allergies, IgE-mediated and non-IgE-mediated.

An IgE-mediated response is when the body reacts to a usually harmless substance by releasing immunoglobulin E antibodies. These attach to mast cells that then release granules and chemicals such as histamine, cytokines, leukotrienes, heparin and proteases. Many mediators cause characteristic allergy symptoms such as rashes, hives, itching, streaming eyes, congested or runny nose, asthmatic breathing, tingly mouth or lips, swelling and anaphylaxis in severe cases.

An IgE-mediated food allergy generally shows symptoms within hours, whereas a non-IgE-mediated food hypersensitivity can take from hours to weeks to manifest. According to the Royal Children’s Hospital Melbourne, “Non-IgE-mediated food allergies are caused by a reaction involving other components of the immune system apart from IgE antibodies. The reactions do not appear immediately after the ingestion of the food and usually relate to reactions in the gastrointestinal tract such