Coeliac Disease, Gluten Sensitivity or Wheat Allergy
Three conditions that get treated as one. Only one damages the gut, only one has a definitive test, and the order you investigate them in decides what you can find out.
Part of the Complete Coeliac Disease Guide.
Key fact: Three different conditions get called "gluten problems". Only one of them damages the gut, only one has a definitive test, and only one carries long-term risk if ignored — which is why coeliac disease has to be excluded first, before any gluten-free experiment.
Three different things
| Coeliac disease | Gluten sensitivity | Wheat allergy | |
|---|---|---|---|
| What it is | Autoimmune condition | Not established — a symptom pattern | Allergic reaction |
| Trigger | Gluten in wheat, barley, rye | Possibly gluten, possibly other wheat components | Wheat proteins |
| Onset after eating | Cumulative — damage over time | Hours | Seconds to minutes |
| Antibodies | Yes — tTG, EMA | None | IgE to wheat |
| Gut damage | Yes | No | No |
| Diagnostic test | Blood antibodies plus biopsy | None exists | Skin prick or specific IgE testing |
| Do traces matter? | Yes — even without symptoms | Generally dose-related | Yes, potentially seriously |
| Long-term risk if ignored | Anaemia, osteoporosis, subfertility, rarely lymphoma | None established | Anaphylaxis in severe cases |
Coeliac disease
An autoimmune condition in which gluten triggers the immune system to damage the lining of the small intestine. It is diagnosable, it is permanent, and the treatment is a strict lifelong gluten-free diet. It affects roughly one in a hundred people, and a large proportion remain undiagnosed.
The defining feature for this comparison: damage happens whether or not you feel it. Someone with coeliac disease who eats a small amount of gluten and notices nothing has still had an immune response in the gut. That is why "a bit of gluten doesn't bother me" is not reassurance, and why strictness is required in a way it is not for the other two.
Non-coeliac gluten sensitivity
This describes people who get symptoms after eating gluten-containing food, but who do not have coeliac disease or wheat allergy. Bloating, wind, abdominal discomfort, fatigue and foggy-headedness are the common complaints.
- There is no specific diagnostic test. It is defined largely by improvement on a gluten-free diet once the other two have been excluded
- No antibodies are produced and there is no apparent damage to the gut lining
- The mechanism is unclear, and it is genuinely debated whether gluten is the culprit at all
- It is not known to carry long-term complications, which changes how strict you need to be — the diet is for symptom control, not damage prevention
That last point is the practical difference. Someone with gluten sensitivity who has a slice of cake is managing symptoms; someone with coeliac disease who does the same is causing damage.
Wheat allergy
A true allergy to proteins in wheat, mediated by IgE. It behaves like other food allergies: reactions come on fast, usually within seconds or minutes, and can include hives, swelling, wheeze, vomiting and, at the severe end, anaphylaxis.
- It is to wheat, not to gluten specifically — so barley and rye may be fine, and a gluten-free product containing other grains may still be a problem if contaminated with wheat
- It is diagnosed by allergy testing alongside the history
- It is commoner in children, and often outgrown
- Adrenaline auto-injectors are prescribed where reactions have been severe
Rapid symptoms after eating wheat — lip or tongue swelling, throat tightness, wheeze, widespread hives, faintness — are an allergy question, not a coeliac question, and need urgent assessment. Call 999 for breathing difficulty, throat swelling or collapse.
It may not be the gluten at all
Wheat contains more than gluten. It is also high in fructans, a fermentable carbohydrate in the FODMAP group, and studies have repeatedly found that people who identify as gluten-sensitive often react to fructans rather than to gluten itself.
This matters because it changes the solution. If fructans are the problem, a low FODMAP approach — which is structured, temporary and reintroduces foods systematically — is more informative and less restrictive than cutting gluten indefinitely. Fibre and IBS covers the related question of which fibres help and which do not.
Why the order matters
Exclude coeliac disease first, while still eating gluten. Coeliac UK is unambiguous: do not try a gluten-free diet as a first step, because it prevents an accurate coeliac test. Once gluten is removed, antibodies fall and the gut heals, and getting a definite answer later means eating gluten again for at least six weeks.
The cost of getting the order wrong is not theoretical. It is the difference between a diagnosis with monitoring, family screening, bone health assessment and dietetic support, and a self-imposed restriction with none of those.
How to work out which you have
| Step | What it involves |
|---|---|
| Keep eating gluten | Whatever you suspect. Everything below depends on it |
| Get coeliac serology | Total IgA and IgA tTG. See getting tested |
| Raise rapid-onset symptoms separately | If reactions are within minutes, allergy assessment is the right route rather than coeliac testing |
| If coeliac is excluded, then experiment | A structured trial — ideally low FODMAP with reintroduction rather than open-ended gluten avoidance — with dietetic input |
| Reassess if symptoms persist | Persisting symptoms on a gluten-free diet suggest something else is going on |
Where IBS fits
A large proportion of people who arrive at "I think I'm gluten intolerant" turn out to have IBS. The symptom overlap is close to complete, and the fructan point above explains much of why wheat is so often identified as the trigger.
Coeliac serology is part of the standard workup before settling on an IBS diagnosis in an adult, precisely because coeliac disease can mimic IBS exactly. IBS red flags covers what else needs excluding before accepting the label.
Frequently Asked Questions
What is the difference between coeliac disease and gluten intolerance?
Coeliac disease is an autoimmune condition where gluten causes the immune system to damage the small intestine. It produces antibodies, is confirmed by biopsy, and carries long-term risks including anaemia, osteoporosis and subfertility. Non-coeliac gluten sensitivity produces no antibodies and no gut damage, has no specific diagnostic test, and has no established long-term complications.
Is there a test for gluten sensitivity?
No. There is no specific diagnostic test for non-coeliac gluten sensitivity. It is identified by symptoms improving on a gluten-free diet once coeliac disease and wheat allergy have been excluded, which is why those two have to be tested for first, while still eating gluten.
Can I be allergic to gluten?
Wheat allergy is an allergy to proteins in wheat rather than to gluten specifically, and it behaves differently from coeliac disease. Reactions come on within seconds or minutes and can include hives, swelling, wheeze and, at the severe end, anaphylaxis. It is diagnosed with allergy testing.
Why do I feel better without wheat if I do not have coeliac disease?
Wheat contains fructans as well as gluten, and fructans are fermentable carbohydrates in the FODMAP group. Studies have found that many people who identify as gluten-sensitive react to fructans rather than gluten. A structured low FODMAP trial with reintroduction is usually more informative and less restrictive than avoiding gluten indefinitely.
Should I try a gluten-free diet to see if it helps?
Not before coeliac testing. A gluten-free diet makes both the coeliac blood test and the biopsy unreliable, because antibodies fall and the gut lining heals. Get coeliac disease excluded while still eating gluten, then experiment with dietetic input if needed.
References
- National Institute for Health and Care Excellence. Coeliac disease: recognition, assessment and management (NG20). nice.org.uk
- NHS. Coeliac disease. nhs.uk
- NHS. Coeliac disease: diagnosis. nhs.uk
- Coeliac UK. Non-coeliac gluten sensitivity. coeliac.org.uk
- National Institute for Health and Care Excellence. Irritable bowel syndrome in adults: diagnosis and management (CG61). nice.org.uk
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Do not start a gluten-free diet before coeliac testing is complete, as doing so makes the tests unreliable. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.