Food Allergies: IgE and Non IgE Mediated (formerly known as IGg*)
IgE (immunoglobulin E):
Most of us recognize the following allergy symptoms: rash, hives, swelling, breathing difficulties, etc.
This type of allergy is caused by IgE (immunoglobulin E) in the body. This is the type of allergy that is being tested for in the common skin prick or scratch test.
Non IgE mediated (Formerly known as: IgG, immunoglobulin G):
The other type of allergy is less obvious, and the symptoms can appear many hours (even days) after exposure. This type of allergy, non IgE mediated food allergy (which also used to, up to very recently, be referred to as an intolerance or IgG intolerance) can present with many different symptoms, and the symptoms can vary from person to person. These present with delayed reactions and mostly manifest with inflammation in (gastrointestinal) tissue. It may take up to 72 hours after consumption of the food for symptoms to be observed. Symptoms can vary widely. Some examples: stomach pain, gas, cramping, eczema, delayed gastric emptying, diarrhea and/or constipation. Other symptoms may include: nasal congestion, wheezing or asthma type symptoms, congestion in the ears often leading to recurrent ear infections, and eczema. In some children, non IgE mediated food allergies can cause brain inflammation resulting in behavioural issues resembling ADHD and autism. Many allergists are still using the older terminology of “IgG intolerances” aren’t even aware of this new terminology.
Testing for Allergies, and Intolerances:
non IgE mediated food allergy and most allergists: Unfortunately most allergists do not think outside the box – if it’s not something they can see physically, like on the skin prick test, then it can’t be related to allergies of any sort. In their mind, there’s just no possibility that non IgE mediated food allergies can produce unseen effects on the body and brain. Also, it’s such new and cutting-edge research that the information isn’t widely known or accepted yet. Since non IgE mediated food allergies produce delayed effects (could be 8 hours later, could be 3 days later) it’s hard to link the two. However, since IgE allergies produce immediate effects it is easy to see, test, and prove.