An allergic reaction is simply an overreaction of our immune system. With a food allergy, the body’s immune system mistakenly recognises common proteins that are present in the foods we eat as “dangerous”. An immune response is set in motion aimed at neutralising the “dangerous protein”. This wrong immune response is responsible for the symptoms experienced by a food allergic child or grown-up.
What makes diagnosis difficult is the fact that the symptoms don’t always appear straight away. The immune response of food allergy may occur within minutes after a child eats or drinks. This immediate on-set reaction involves so called IgE antibodies. This kind of reaction is easy to diagnose with validated tests.
In some cases, the immune system can take longer to react, several hours or even days. In this case, immune cells are responsible for the delayed on-set of the food allergic reactions and these are difficult to diagnose in allergy tests. And this delayed on-set reaction is called non IgE mediation.