What are IgE-mediated, life-threatening food allergies?

Did you know that food allergies can be life-threatening? It's true. In fact, anaphylaxis is a life-threatening allergic reaction that can occur when someone eats a food to which they are allergic. In most cases, the type of food allergy that is life-threatening is IgE-mediated food allergy. In this article, we will discuss IgE-mediated food allergy and why it can be so very concerning.

So what is IgE? And what's its role in life-threatening food allergies?

IgE is a molecule found on the outsides of allergy cells, specifically mast cells. IgE binds to allergens. It’s a lot like a lock on the door of your house. Only a specific key fits the lock. That lock-and-key that then allows the door to be unlocked and opened. In, for example, a little girl with peanut allergy, she has mast cells that have peanut-specific IgE on them. Much like the lock on a door, only a specific key can unlock that cell – in this case, peanut protein. 

What happens when IgE activates an allergy cell?

When peanut binds to peanut-specific IgE, that binding sends an activation signal to the cell’s nucleus. The nucleus of the cell then signals for the release chemical-filled granules. This process is called “degranulation.” 

IgE-mediated life threatening food allergy reactions involve mast cells, IgE, and the food allergen.
IgE-mediated life threatening food allergy reactions involve mast cells, IgE, and the food allergen.

When the mast cell degranulates, the chemicals inside the granules are released into the surrounding tissues and blood stream. Those chemicals, such as histamine (itching!) and vasodilators (swelling and drop in blood pressure!) and bronchoconstrictors (trouble breathing!) and other chemicals are deposited locally. This means that, in the case of someone with food allergy ingesting their allergen, chemicals are released from granules into the stomach, causing nausea and vomiting. This reaction can also spread throughout the body. This can result in hives, swelling, trouble breathing, and drop in blood pressure, among other symptoms. 

Non-IgE-Mediated, Severe Food Allergies

Just because a child has a non-IgE-mediated food allergy does not mean their food allergy should be taken any less seriously. One example of a non-anaphylactic but severe food allergy is food protein-induced enterocolitis syndrome (FPIES). More on FPIES here.

“But my kiddo has only ever had hives from his food allergy. Does he have a life-threatening food allergy?”

Hives one times does not mean hives the next time. Having hives as a manifestation of IgE-mediated food allergy reaction – meaning your kiddo ate a food and quickly developed hives on his body beyond where the peanut butter touched his skin (so he got hives all over but on touched peanut butter on his fingers) means there is a system-wide response to that peanut butter occurring. Thankfully, only hives resulted (no disrespect to hives – soooo itchy – but better than life-threatening symptoms!). This reaction suggests he has IgE-mediated peanut allergy and should avoid peanut and carry an epinephrine auto-injector to treat anaphylaxis.

What is the treatment for IgE-mediated, life-threatening food allergies?

Epinephrine is the treatment for an IgE-mediated severe allergic reaction, also called anaphylaxis. Epinephrine is the medication that not only stops the signs and symptoms of anaphylaxis but also shuts down the allergy cells that are causing the reaction. More on epinephrine here.

Immunotherapy, such as oral immunotherapy (OIT), can be considered as a treatment to build a person’s tolerance to an allergenic food. While it can be very helpful in making the immune system less sensitive to the food allergen, it carries its own risks. Check learn more below:

See an allergist about life-threatening food allergies.

As more and more children (and adults) are managing food allergies, it's important that everyone with a food allergy see a board-certified allergist. The allergist can determine what type of food allergy is present and provide best treatment options.


Thanks for reading this post “What are life-threatening food allergies?” Do you have any questions about food allergies? Reach out to me! And be sure to check out my other blog posts and podcast episodes about all things food allergy. Thanks for reading!
– Dr. Hoyt

P.S. Food allergy testing can be super confusing, so I've created this awesome ebook to clarify the facts from the fiction! Get your copy today!


Are you in need of an allergist in your area? Check out these allergist finder tools:

AAAAI Allergist Finder: https://allergist.aaaai.org/find/
ACAAI Allergist Finder: 
https://acaai.org/locate-an-allergist


Do you have food allergy questions? Have them answered by Dr. Alice Hoyt, Pam, and guests on the podcast!

Submit your questions HERE!


A note from Dr. Hoyt

I have talked about a non-profit…

Pam and I volunteer with the non-profit The Teal Schoolhouse. Its primary program is Code Ana. Code Ana equips schools for medical emergencies like anaphylaxis.

Code Ana’s Online Epinephrine Training Program helps support that goal. Through this program, you will educate yourself while you support this important mission!

A medical emergency response plan is important for everyone at any school. Code Ana's program Med-E Ready is a comprehensive approach to school-focused medical preparedness. This program guides schools through the process of creating a medical emergency response plan. A response team is also developed! This is one of the most important components of a school's food allergy policy!

Does your kiddo’s school have Code Ana?


You've just read Dr. Hoyt's post “What are life-threatening food allergies?” Remember, she's an allergist, but she isn't your allergist, so talk with your allergist about what you've just learned!

Who do you know that may enjoy this article? Share it!

Share on facebook
Post it!
Share on twitter
Tweet it!
Share on pinterest
Pin it!
Scroll to Top