A food allergic reaction is the misguided response of the immune system to a certain protein in food, resulting in a number of specific symtoms1.
We all have an immune system to protect us from infections. Its role is to keep us healthy by ‘fighting off’ the viruses and bacteria that can make us ill2. An allergic reaction is an overreaction of our immune system to a usually harmless substance in the environment1.
With a food allergy, the body’s immune system reacts to certain proteins found in food. The immune system views the food protein as ‘dangerous’ and this triggers the release of chemicals to defend the body against it2. The chemicals released are known as ‘allergen antibodies’1. This immune response is responsible for the symptoms experienced by adults and children with a food allergy.
Most food related allergic reactions occur within two hours of ingestion; often symptoms will appear within minutes2. These immediate immune responses are known as IgE-mediated reactions. In some cases, however, the immune system can take longer to react, several hours or even days. This delayed reaction, known as a non-IgE-mediated reaction, is often seen when children develop allergic symptoms such as eczema3.
These two different reactions can be important in the diagnosis of food allergy. IgE-mediated reactions produce IgE antibodies. These antibodies can be detected easily in validated allergy tests3 and are an important tool in diagnosing food allergy. Unfortunately there are no reliable tests to diagnose non-IgE-mediated allergic reactions3. Diagnosis of these reactions is based on a number of other measures, such as patient history, dietary changes and in some cases food challenges2.
With a food allergy, the body’s immune system reacts to certain proteins found in food. The immune system views the food protein as ‘dangerous’ and this triggers the release of chemicals to defend the body against it
- ASCIA, 2016, Food Allergy, Australasian Society of Clinical Immunology and Allergy, viewed 17 May 2016, http://www.allergy.org.au/patients/food-allergy/food-allergy
- ACAAI, 2014, Food Allergy, American College of Allergy, Ashtma and Immunology, viewed 17 May 2016, http://acaai.org/allergies/types/food-allergies
- Motala & Fiocchi, 2012, Cow’s milk allergy in children, World Allergy Organisation, viewed 17 May 2016, http://www.worldallergy.org/professional/allergic_diseases_center/cows_milk_allergy_in_children/