Food Sensitivity vs. Food Allergy: What’s the Difference?

Understanding the difference between a food allergy and food sensitivity can be tough. The two have a lot of overlap when it comes to symptoms. Plus, the most common food allergy culprits are also responsible for food sensitivities and intolerances. 

So what’s the difference between these two very common conditions? The answer is in the immune system’s response to foods.  

What is a food allergy?

A food allergy is an immune reaction. When someone with a food allergy eats a certain food, their immune system goes into overdrive. That’s why food allergies are also called “food hypersensitivity reactions.” 

Many people develop food allergies during childhood. It’s more common to develop a new food allergy as a child, but you can develop a food allergy at any age.

There are two main types of food allergies:

1. IgE-mediated reactions

2. Non-IgE-mediated reactions

IgE (immunoglobulin E) is a type of antibody that plays a role in your immune system’s allergic response. The difference between the two types of food allergies has to do with how your immune system reacts when faced with a particular food. 

IgE-mediated reactions

People who have IgE-mediated food allergies develop symptoms as soon as they come in contact with their allergen. These symptoms include:

• Hives

• Cough

• Chest tightness

• Wheezing

• Nausea

• Vomiting

• Swelling

These types of food allergies can lead to anaphylaxis, a life-threatening condition that requires immediate treatment with epinephrine. 

Non-IgE-mediated reactions

People with non-IgE-mediated food allergies develop symptoms within hours of coming in contact with their allergen. These symptoms include:

• Stomach pain

• Nausea

• Vomiting

• Bloody stool

• Weight loss

• Reflux

• Food impaction (feeling like something is stuck in your throat)

Examples of non-IgE-mediated reactions are eosinophilic esophagitis and food protein-induced enterocolitis syndrome (FPIES). These types of food allergies do not cause anaphylaxis.

What are common food allergies? 

Up to 90% of food allergies are from 8 foods:

• Cow’s milk

• Eggs

• Peanuts

• Tree nuts

• Fish

• Shellfish

• Wheat

• Soy 

What is a food sensitivity or intolerance?

A food sensitivity, or intolerance, is when a specific food makes you feel sick whenever you eat it. Symptoms include:

• Vomiting

• Diarrhea

• Rash

• Headaches

Some of these symptoms overlap with food allergy symptoms. The difference is that these symptoms aren’t the result of an immune reaction. So a food sensitivity won’t lead to anaphylaxis.

It’s not always clear why someone develops a food sensitivity. But, for some people, the cause can be due to a genetic reason. Some people can’t break down certain proteins or sugars in foods, and this leads to a food sensitivity. 

A very common example is lactose intolerance. People with lactose intolerance can’t break down lactose — the sugar in milk. Every time they drink milk (or eat milk-containing foods) they can experience symptoms like stomach upset, indigestion, and diarrhea. 

What are common food sensitivities?

About 1 in 5 people have a food sensitivity. You can develop a food intolerance to any food at any point in your life. Some common food sensitivities include:

• Cow’s milk and dairy

• Fruit and fruit-based sweeteners

• Alcohol

• FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols)

How do you test for food allergies and sensitivities?

Testing for food allergies can be tricky. That’s because some people aren’t always sure which specific food is causing their symptoms. And, in some cases, people can have allergies to multiple foods. 

You’ll likely need a skin-prick test to see if you have a food allergy. In this test, an allergist pricks your skin with several needles. Each needle contains a very small sample of common causes of food allergies. Since even a small amount of exposure can lead to anaphylaxis, the test has to be done under medical supervision. 

After a skin-prick test, you may need to do a food challenge. This is when you eat a small amount of food to see if you have a reaction. Again, this is usually done with medical supervision in case you have a severe allergic reaction. 

Testing for a food sensitivity is less straightforward. There are at-home kits that test for food sensitivities. But it’s not clear if these results are reliable.  

Most of the time, you can figure out if you have a food sensitivity based on your symptoms and eating patterns. You can keep a food diary to help keep track of your symptoms. You can also try an elimination diet to help pinpoint specific triggers. 

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Written by:

Jennifer Sample, MD

After a fellowship, Dr. Sample worked as the medical director at the University of Kansas Hospital Poison Center (The University Of Kansas Health System Poison Control Center), which served the state of Kansas for poison exposures. In 2007, she returned to Children’s Mercy Hospital in Kansas City, Missouri, as a consultant in clinical pharmacology and medical toxicology.

Edited by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

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