Am I allergic to gluten? Why skin prick tests miss the mark.

Gluten allergy is a concern for many folks who notice symptoms after eating gluten-filled foods like bread, bagels, and pasta or even sneaky glutinous foods such as soy sauce, soups, or cold cuts. If you’ve asked yourself, “Am I allergic to gluten?” your first stop might have been the doctor’s office to get a skin prick test. A skin prick test is an excellent way to identify an allergy (1).

Feeling sure that the test will confirm a gluten allergy, you begin mentally preparing to make the big shift to a gluten-free life and say goodbye to your symptoms.

But 20 minutes later, your skin does not react whatsoever, and the nurse tells you that you’re not allergic to gluten after all.

You give an outward smile, but internally you feel completely confused.

Why do you feel like crap every time you have a gluten-filled meal if you aren’t allergic? Could the test be wrong?

Well, my friend, you are asking the right questions. Let’s talk about how conventional allergy tests miss the mark.

Am I allergic to gluten, or do I have celiac disease?

An allergic response to glutinous foods is classified as a wheat allergy. And just like an allergy to peanuts, shellfish, or pollen, a wheat allergy can be quite serious. This is due to the immune system’s response when it comes into contact with an allergenic trigger.

During an allergic reaction, your immune system produces an antibody called immunoglobulin E. This antibody leads to a cascade of chemical releases, including a lot of a protein called histamine. A true allergy can lead to swelling, itching, sneezing, and even nausea, vomiting, diarrhea, fainting, or airway constriction.

However, your immune system has an entirely different reaction when you have celiac disease. Instead of producing IgE antibodies to wheat, your immune system makes super-specific IgA and IgG antibodies triggered by gluten.

This different immune response is because celiac disease is an autoimmune condition and not an allergy. Symptoms of celiac disease may overlap those of wheat allergy, like nausea and vomiting. But celiac symptoms can also include symptoms like fatigue, anemia, weight loss or weight gain, and nutrient deficiencies.

However, celiac can not be diagnosed with a skin prick test. A standard test for celiac disease is a blood test of tissue transglutaminase-IgA. Your doctor might also perform an endoscopy of your small intestine in order to take a biopsy of your intestinal tissue. This test will show atrophy and damage to the small intestine, a hallmark of untreated celiac disease.

Am I allergic to gluten, or do I have non-celiac gluten sensitivity?

Non-celiac gluten sensitivity (NCGS) is challenging to diagnose because clear diagnostic markers have yet to be established. Because of this, NCGS is known as a diagnosis of exclusion. To learn if you have NCGS, you must first test negative for celiac disease and wheat allergy. These other similar diagnoses are first excluded.

Even though NCGS currently lacks diagnostic markers, it is a very real condition that affects an estimated 6% of people worldwide (2). But because there is a lack of studies on NCGS, this estimate could be much higher or much lower…we just can’t know for sure. 

Symptoms of NCGS often overlap with celiac, including the classic abdominal bloating and diarrhea but also headache, atopic dermatitis, fatigue, depression, and canker sores (3).

What should I do if I think I’m allergic to gluten? (Or have celiac disease or NCGS?)

If you have a gut feeling that you might be reacting to gluten, your first response might be to stop eating it altogether. But if you want testing done to confirm a diagnosis, pause before you rehaul your diet. To be correctly diagnosed with celiac disease, you must continue to eat gluten until after completing your testing. If you begin eating a gluten-free diet or even smaller amounts of gluten, you can have a false-negative celiac result.

Request a celiac panel if you have discovered that you are not allergic to gluten via a skin prick test. If your health care practitioner is reluctant, insist! Or find another licensed practitioner to work with. It is your body, your health, and your happiness at stake.

If you test negative for celiac, ask your provider about NCGS. You may be asked to do an elimination-reintroduction diet, or you can do one on your own. At this stage, an elimination diet is an excellent tool to confirm that gluten is, in fact, what is making you feel so crappy.

Let’s talk if you need help with an elimination diet or are worried that a gluten-free life will be dull, joyless, and too challenging. That’s why I’m here! Go entirely gluten-free in 7 days with my course, Easy Peasy Gluten Freezy.

  1. https://pubmed.ncbi.nlm.nih.gov/29552869/
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5677194/
  3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5897856/