Difference between classic IgE food allergies and delayed IgG food allergies

There are various reasons why a food can cause problems, among them a classic IgE food allergy (type I) and a delayed IgG food allergy (type III), the latter is also referred to as food intolerance. What both allergies have in common is that the immune system is involved however there are some differences in the way it responses.

Classic IgE food allergy

A classic type I allergy is when the immune system produces specific IgE antibodies (immunoglobulins of the subclass E). These antibodies lead to an immediate allergic reaction. The symptoms appear within seconds or minutes: severe swelling, breathing difficulty, rash, itching skin or even anaphylactic shock.

Someone who has a type I allergy will most probably know which food is causing the reactions because the symptoms will appear right away. Skin-prick or scratch tests are usually performed for confirmation of a type 1 allergy, but an IgE blood test can also be conducted which is a bit less invasive.


Delayed IgG food allergy

A type III food allergy is when the immune system produces specific IgG antibodies (immunoglobulins of the subclass G). These antibodies can lead to inflammatory processes. The symptoms can appear up to three days after the consumption of a trigger food.

It is very difficult to pinpoint which food is giving you the reaction in this case because of the delay in symptoms appearing. An IgG blood test will help to localise and limit the suspects, identifying exactly which foods are causing inflammation.

With ImuPro you will only have to avoid foods with elevated IgG antibody values. This means that you can maintain a diverse and varied diet and don’t need to restrict yourself unnecessarily. For example, you may need to avoid salmon but be able to eat all other fish. After a certain period of avoidance, you may reintroduce one food after the other into your diet and monitor your symptoms. This provocation phase is the crucial step to identify your personal “trigger foods”.


Quick Comparison Table: IgE food allergy vs. IgG food allergy

Differences IgE food allergy (type I) IgG food allergy (type III)
Immune Response Production of IgE antibodies

Release of histamine mediated by IgE antibodies

Production of IgG antibodies

Release of inflammatory mediators caused by binding of IgG antibodies

Nature of food allergy symptoms E.g. itching, red skin, anaphylaxis, swelling of the mucous membranes Chronic inflammatory ailments, e.g. Irritable Bowel Syndrome (IBS), constipation, flatulence, diarrhoea, Crohn’s Disease, eczema, psoriasis, migraines, obesity, joint pain, etc
Onset of symptoms Immediate reaction within a few minutes After several hours to three days
Diagnostics Skin-prick/scratch test or IgE blood test IgG blood test + food challenge test