3 Misperceptions and Myths About Food Allergies

allergy & immunology Jun 03, 2022
A person in a white coat is rejecting a bowl of nuts, representing caution due to potential food allergies.

Recently, singer and musician Halsey shared her recent allergy testing results on TikTok along with the news of her recent diagnosis of Ehlers-Danlos syndrome (EDS), mast cell activation syndrome (MCAS), and Sjogren’s Disease. Pictured were the telltale red welts we inflict day in and day out in allergy clinic with our scratch tests and a long list of foods to which she was possibly allergic.

Halsey has a history of being open and advocating for improved health care following her diagnosis of endometriosis in 2016.

As a fellow Sjogren’s patient and allergy/immunology physician, Halsey, I want to thank you for adding your face and powerful voice to commonly misunderstood and underdiagnosed invisible illnesses.

I thought it to be a great opportunity to share three misperceptions and myths that I routinely encounter about food allergies, intolerances, and testing.


1. Food allergy is a clinical diagnosis that is supported by IgE testing. 

Food allergy is an immune response mediated by immunoglobulin E (IgE) antibodies resulting in the degranulation of mast cells. Reactions are reproducible and nearly always occur within minutes of exposure to the trigger food. Symptoms are suggestive of the release of histamine, tryptase, and dozens of other chemical mediators found within the mast cells. They include itching, swelling of the lips or tongue, vomiting, diarrhea, hives, trouble breathing, low blood pressure, and loss of consciousness. There are no hidden food allergies.

Anaphylaxis occurs when two or more organ systems are involved. The only treatment for acute anaphylaxis is intramuscular epinephrine. The role of allergy skin testing or serum IgE testing (RAST testing) is confirmatory. An elevated level of IgE in food on its own is called sensitization. Elevated IgE, along with a history of clinical symptoms, is allergy.

Why the distinction? Many of us eat foods we are sensitized to all day every day and don’t have any problems with them. There are a lot of false positives on both serum and skin testing.

Many times, unnecessarily dietary restriction, anxiety, and fear result but in the worst-case scenario, we see this restriction result in loss of tolerance, and subsequent diagnosis of an IgE mediated allergy.


2. Food sensitivity testing is a waste of time, energy, and money. 

The most common food sensitivity tests measure immunoglobulin G (IgG) antibodies. IgG is the body’s memory antibodies. They are a great way to tell if you have made and maintained memory of prior infections or vaccination, commonly referred to as titers. So food memory should tell us if a food is a problem, right?

Wrong. Many times IgG actually signals tolerance. The other issue is that food intolerances or sensitivities are not due to an immunologic response but are due to interactions between the food, microbiome, and products of the digestion or fermentation process.
It can be incredibly beneficial for patients to keep a food and symptom journal and review it with a trained dietician who can help identify possible triggers such as salicylates, histamine, or FODMAP. They can also help with an elimination trial if necessary and re-introduction of foods as soon as possible. The least restrictive diverse diet is the goal for convenience and is also associated with improved health outcomes.


3. There is no substitute for a thorough medical history and a trusting therapeutic relationship in the care of invisible illness patients. 

This is medicine that cannot be rushed. It requires active listening and conscious, deliberative “slow thinking” that internists (and pediatricians) pride themselves on. Complicating things further, most invisible illness patients have played the game of hot potato as they are passed off from one specialist to the next in search of a diagnosis. Data would also tell us that most will have a history of adverse childhood events and trauma and yet have encountered a medical system that is far from trauma-informed.


So what can we do?

1. Don’t order food IgE testing to screen for food allergies.
2. Don’t recommend food sensitivity testing but instead encourage patients to keep a food and symptom journal. They can consider using the money they saved towards the cost of a visit with a dietician.
3. Get curious. Listen to your patient’s history: It is their lived experience. Don’t discount it. If you don’t know what is causing their symptoms, be honest with them (and then ask for help).

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