IGE or Non-IGE Allergy

The initial stages of your allergy baby journey can, quite frankly, be traumatic. After weeks, even months, of caring for a constantly crying and distressed infant, hearing that your beautiful baby may have an allergy can be an unexpected blow.

In order to navigate the ocean that is infant allergies, the first expression we need to grasp is “IgE”. IgE refers to the most well understood type of allergic reaction. The vast majority of people who experience an immediate allergic reaction, will be having an IgE reaction.

IgE cells, found in your immune system, help the body fight viruses, bacteria and toxins. In the case of people who experience IgE reactions, these cells confuse the protein in foods for disease and start to attack them. The strength of the reaction varies from mild to life threateningly severe (anaphylactic reactions).

IgE reactions are confirmed by skin prick tests and blood tests. These tests are thought to identify 95% of all allergic reactions that will end in anaphylaxis. If your child is having this type of reaction, their care will be managed by an immunologist (or an allergist) and a dietician.

The term Non-IgE reaction is a blanket term, thought to account for around 60% or more of all allergic reactions, and includes all allergic responses which don’t involve Immunoglobulin E. At this time, non-IgE reactions are not well understood. With a shortage of accurate or reliable tests to confirm non-IgE reactions, obtaining a respected diagnosis can be a challenge.

All delayed reactions, those starting after 2 hours or more after eating a food, are non-IgE reactions and are usually managed by the GP and Dietician.

An immediate reaction which has been confirmed as a non-IgE reaction, will be managed by a GP and a dietician. Only if the reaction is witnessed by a health professional, will an immunologist (or an allergist or a paediatrician knowledgeable in allergic conditions) become involved. The type of specialist assigned to your baby or child is often determined by local area availability. It can take years of investigations to get a proper diagnosis for immediate non-IgE reactions. For some people who experience non-IgE mediated anaphylaxis, a more accurate diagnosis than idiopathic anaphylaxis may never be sought or achieved.

Delayed onset CMPA, FPIES and mast cell mediated allergies are typically non-IgE reactions.

It’s fairly common for people to experience mixed reactions with immediate IgE symptoms and delayed non-IgE symptoms as part of the same episode.

Between 5 and 30% of non-IgE reactions are thought to have the potential to become IgE reactions. There is currently no reliable way to establish or predict which cases will become IgE.

For more information about IgE and non-IgE reactions, there’s a wide selection of resources available online.

Further Reading

https://www.isitcowsmilkallergy.co.uk/en-gb/getting-my-baby-diagnosed/types-of-cma

http://www.worldallergy.org/professional/allergic_diseases_

https://www.aaaai.org/conditions-and-treatments/conditions-dictionary/immunoglobulin-e-(ige)

http://www.mastcellaware.com/mast-cells/about-mast-cells.html

https://www.rch.org.au/uploadedFiles/Main/Content/allergy/Non%20IgE%20Food%20Allergy.pdf

https://aacijournal.biomedcentral.com/articles/10.1186/1710-1492-2-2-78