Food Allergy vs. Food Sensitivity: What’s the Difference (and Which Test Is Right for You)?

You’ve had the skin prick or standard allergy blood test, and everything came back “normal.” Yet every time you eat certain foods, you bloat, ache, or feel off. You’ve tried cutting things out, reintroducing them, and still can’t find what’s triggering your symptoms.

Or maybe you just know your digestion is off and you haven't been able to figure out why? Maybe you are experience frequent gas and bloating, poor stools or chronically loose or constipated bowel movements. Perhaps you suffer from eczema, psoriasis or IBS?

If that sounds familiar, you might not be dealing with a food allergy at all, but a food sensitivity. These two reactions often get lumped together, but they’re very different and knowing which one you actually have determines which test will give you real answers.

It's not uncommon for patients to come to us saying they have seen the specialist (i.e. gastroenterology, or GI doc), and they told them "their diet has nothing to do with their digestion", or the dermatologist might also say their "diet has nothing to do with their chronic skin rash". This is complete nonsense! Your digestion has to do with everything! From absorption to nutrients, to recirculation of hormones, even to the production of neurotransmitters that control how you think and feel and how well your immune system functions are all in impacted by how well your digestive system is functioning and how healthy your microbiome is.

From absorption to nutrients, to recirculation of hormones, even to the production of neurotransmitters that control how you think and feel and how well your immune system functions are all in impacted by how well your digestive system is functioning and how healthy your microbiome is.

What Food Allergy Testing Looks For

Food allergies involve an IgE immune response — the same type of reaction behind hives, swelling, or anaphylaxis (dangerous swelling of the throat and airways after exposure). These symptoms happen quickly, usually within minutes to a few hours of exposure.

Allergy testing is typically done through:

• Skin prick testing

• Serum IgE blood testing

  
  

Both look for immediate reactions. If you eat peanuts and your throat starts to swell, that’s an IgE-mediated food allergy. These are serious, often lifelong, and managed by strict avoidance and sometimes emergency medication.

Food Sensitivity Testing: The Other Side of the Immune System

Food sensitivities are not the same thing. They usually involve IgG or IgA immune pathways, and symptoms show up hours or even days later. The response is delayed, so you don’t always connect the dots.

Common symptoms include:

• Digestive upset (bloating, constipation, or diarrhea)

• Fatigue and brain fog

• Skin rashes or acne

• Joint pain or inflammation

• Mood changes or anxiety

  
  

Unlike allergies, food sensitivities are not dangerous, but they are inflammatory and can make life very uncomfortable. Over time, they can contribute to chronic inflammation, gut permeability, or immune dysregulation.

Clinically, we've seen food sensitivities be drivers for many chronic conditions including asthma, eczema, IBS, IBD, chronic heartburn/GERD, worsened autoimmune disease symptoms, chronic muscle and joint aches and pains, fibromyalgia, psoriasis and more.

Why Allergy Tests Often Miss the Problem

Standard allergy testing only checks for IgE reactions. If your immune system is reacting through IgG or IgA instead, those tests come back negative, even though your body is still mounting an inflammatory response.

That’s why people say things like “My allergy test was negative, but I still can’t eat eggs.” The test wasn’t wrong. It just wasn’t the right kind of test.

How Food Sensitivity Testing Works

Functional labs now offer comprehensive blood testing that measures IgG reactivity to a broad list of foods. Depending on the panel, that can range from 90 to over 200 items.

Here’s what you can expect:

1. Order the test online — no appointment required.

2. Collect your sample — (usually a simple finger prick) and mail it to the lab.

3. Get your results — with a clear breakdown of low, moderate, and high reactivity foods.

4. Use the results to guide a short-term elimination plan or structured reintroduction process.

   
   

Many people find this data helps narrow down the problem foods and reduce overall inflammation.

It can be a great alternative to an elimination challenge diet, which can take significant time and dedication.

When Food Sensitivity Testing Makes Sense

This type of testing is useful if:

• You’ve tried an elimination diet but still have symptoms

• You have ongoing digestive issues with no clear diagnosis

• You deal with fatigue, skin problems, or inflammatory pain

• You’ve ruled out true food allergies but still react to certain foods

• You want to optimize your health and lower your inflammatory load

  
  

It’s not for everyone, but when used correctly, it can provide clarity and direction — especially when everything else looks “normal.”

Our Approach at Pacific Clinic of Natural Medicine

At Pacific Clinic of Natural Medicine, we offer different types of food reactivity testing depending on where you live and what kind of care you’re looking for.

• For patients in Oregon or Washington: We can explore food sensitivities, intolerances, allergies and help guide our patients through elimination diets if needed.

• For clients in other U.S. states: You can order a Food Sensitivity Test directly through our Functional Labs page. This lab measures immune-based food reactions (IgG) and is available for informational purposes nationwide, (excluding NY, NJ, and RI).

  
  

Your results are sent securely to you, and you can choose to add an optional interpretation session if you’d like help making sense of your results.

What to Expect After You Order

After placing your order online, the process is simple:

1. You’ll receive a collection kit in the mail.

2. Collect your sample following the instructions.

3. Ship it back to the lab using the prepaid envelope.

4. Receive your report securely within about two weeks.

   
   

Your results include a full list of reactive foods and levels of reactivity. If you add an interpretation session, we’ll walk through the results together, talk about patterns, and create a clear plan for next steps.

Image: Rehman et al., Front Immunol 2021 (CC BY 4.0)

Leaky gut is often seen on food sensitivity panels, and it's apparent when many different types of foods are found to be inflammatory. Leaky gut is when there is so much inflammation in the GI tract that larger food proteins are making it past the cells of the intestines and creating immune reactions to foods the person might normally tolerate if their digestive system were healthier. Treating this requires a solid dietary plan and a plan to address healing the lining of the GI tract and the microbiome.

Bottom Line

If you’ve had negative allergy tests but still react to food, you’re probably dealing with sensitivities, not allergies. Testing the wrong thing only prolongs the frustration.

Food sensitivity testing can help you identify your hidden triggers, reduce inflammation, and take the guesswork out of what to eat.

Ready to get answers? Order Your Food Sensitivity Test Here. Results are delivered securely to you, with optional interpretation by a licensed naturopathic physician.

Food Sensitivity Test Kit - 96 General Foods

From$249.00

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Frequently Asked Questions

1. What’s the difference between a food allergy and a food sensitivity?

   1. A food allergy is an immediate IgE immune reaction that can cause hives, swelling, or anaphylaxis. A food sensitivity is a delayed immune response (usually IgG or IgA) that causes inflammation, digestive symptoms, or fatigue hours to days later.

2. Can food sensitivity testing diagnose a medical condition?

   1. No. These tests identify immune reactivity, not disease. The results can guide dietary choices and reduce inflammation but should be used for informational purposes only.

3. How accurate are food sensitivity tests?

   1. Accuracy depends on the lab and the immune markers tested. High-quality panels that measure IgG or IgG4 antibodies can be clinically useful when interpreted in context, especially alongside your history and symptoms.

4. Do I need to stop eating certain foods before testing?

   1. Usually not. You should be eating a variety of foods in the weeks before testing so your immune system has recent exposure. Avoiding foods beforehand can lead to false negatives.

5. What happens after I get my results?

   1. You’ll receive a detailed report showing your food reactivity levels. You can review it on your own or schedule an optional interpretation session to build a clear plan for elimination, rotation, or gut repair.

References:

1. Sicherer SH, Sampson HA. Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and management. J Allergy Clin Immunol. 2018;141(1):41–58. https://doi.org/10.1016/j.jaci.2017.11.003

2. Rehman A, et al. The Gut Barrier, Mucosal Immunity and Nutritional Influences. Frontiers in Immunology. 2021;12:673708. https://www.frontiersin.org/articles/10.3389/fimmu.2021.673708/full

3. Fasano A. Zonulin and its regulation of intestinal barrier function: The biological door to inflammation, autoimmunity, and cancer. Physiol Rev. 2011;91(1):151–175. https://doi.org/10.1152/physrev.00003.2008

4. Vojdani A, Vojdani E, Saidara E. Reaction of foods with human tissue antigens: Possible contribution to autoimmune diseases. Nutrients. 2020;12(9):2695. https://doi.org/10.3390/nu12092695

5. Junker Y, Zeissig S, Kim S-J, et al. Wheat amylase trypsin inhibitors drive intestinal inflammation via activation of toll-like receptor 4. J Exp Med. 2012;209(13):2395–2408. https://doi.org/10.1084/jem.20102660

6. Bentz S, Hausmann M, Piberger H, et al. Influence of food additives on gut barrier function in health and disease. Ann N Y Acad Sci. 2012;1258:52–59. https://doi.org/10.1111/j.1749-6632.2012.06575.x

7. Hoffman M, Lieberman JA. Food allergy vs. food intolerance: Understanding the difference for better patient outcomes. Cleveland Clinic Journal of Medicine. 2018;85(1):44–50. https://doi.org/10.3949/ccjm.85a.17057

8. Sarnelli G, et al. Role of diet and intestinal permeability in the pathogenesis of functional gastrointestinal disorders. Nutrients. 2022;14(4):823. https://doi.org/10.3390/nu14040823

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