The body's immune system responds to any form of allergy. Food allergies can be of two types – one which produces IgG antibodies, classified as food intolerance or Type III allergy; and the other which produces IgE antibodies, classifies as Type I food allergy.
This is a Type I food allergy wherein the immune system produces IgE antibodies in response to an allergen. Immediate allergic reactions begin and symptoms like rashes, itching, breathing difficulties etc. appear within seconds or minutes. This does not require a blood test to confirm its presence, since the food causing it can be easily identified and isolated. Food Allergy Test does not detect these Type I food allergies.
This is a Type III food allergy wherein the body produces IgG antibodies as an immune response, thereby leading to inflammation. Sometimes, the symptoms take up to 3 days to appear, making it tough to identify the food causing the allergy. TO detect and limit the suspect food items, an IgG test can be performed.
Food Allergy Test helps in avoiding foods that cause high levels of IgG antibody values. This helps in enjoying a diet without unnecessary food restrictions. For example, if you are allergic to salmon, you must avoid it, but can continue having other fish. Certain foods can be avoided for a specific period of time and then reintroduced gradually in order to check for allergic reactions or symptoms. This is a vital step in trying to figure out trigger foods.
|Differences||IgE Food Allergy (Type I)||IgG Food Allergy (Type III)|
|Immune response||IgE antibodies produced Histamine release mediated by IgE antibodies||IgG antibodies produced Inflammatory mediators released due to binding of IgG antibodies|
|Food allergy symptoms||Itching, red skin, anaphylaxis, swelling of mucous membranes||Chronic inflammatory ailments like constipation, Crohn's disease, diarrhoea, eczema, flatulence, Irritable Bowel Syndrome (IBS), migraines, psoriasis, obesity|
|Onset of symptoms||Immediate reaction in a few seconds or minutes||Reaction several hours or days later|
|Diagnostics||Prick test or IgE blood test + food challenge test||IgG blood test + food challenge test|