IgE stands for ‘immunoglobulin E’ – a type of antibody in your immune system.
This type of allergy occurs very quickly after a food has been eaten – typically a few minutes and up to 2 hours afterwards. These reactions can be brought on by very small quantities of the food protein which binds to allergen specific IgE receptors in the body leading to the release of histamine and other inflammatory chemicals. Skin prick tests or specific IgE blood tests can help with the diagnosis of this type of allergy, along with an allergy focussed diet history.
Non-IgE mediated allergies
These are delayed type of allergies and occur more than 2 hours to 2 days after eating a particular food. They are still allergies, but different cells in the immune system are involved (not IgE cells). They are more difficult to diagnose than immediate-type allergies.
Unfortunately there are no tests to help with the diagnosis of this type of allergy – the only way to diagnose this type of allergy is to eliminate the suspected food, check for symptom improvement and (crucially) reintroduce the suspected food to confirm if symptoms return.