Synopsis
Evaluate symptoms attributed to gluten without missing coeliac disease, wheat allergy, inflammatory disease or nutritional harm; distinguish gluten from fructan and expectation effects; and use a supervised restriction-and-rechallenge strategy only after appropriate exclusion.
- Non-coeliac gluten sensitivity describes reproducible intestinal or extra-intestinal symptoms related to wheat or gluten exposure after coeliac disease and wheat allergy are excluded; there is no validated diagnostic biomarker.
- Do coeliac serology while gluten is still eaten and complete any required biopsy pathway before restriction, because diet change can normalise both.
- Wheat contains fructans and other components, so improvement on a gluten-free diet does not prove gluten itself was the trigger.
- IgG food panels, hair analysis, kinesiology and unvalidated direct-to-consumer tests do not diagnose coeliac disease, wheat allergy or NCGS.
- Red flags such as weight loss, anaemia, nocturnal diarrhoea, bleeding, fever, family cancer risk or raised inflammatory markers require an organic-disease pathway.
- A dietitian-led, time-limited exclusion followed by structured reintroduction reduces unnecessary lifelong restriction and can identify dose tolerance.
- The nocebo effect and natural symptom fluctuation are real biological and psychological phenomena, not grounds to dismiss the patient's experience.
- Broad gluten-free diets can reduce fibre, whole grains and micronutrients and increase cost; nutritional adequacy is an outcome, not an afterthought.
Key red flags
Rapid urticaria, angioedema, throat symptoms, wheeze, vomiting, hypotension or exercise-associated reaction after wheat suggests IgE-mediated allergy and can be life-threatening.
Blood in stool, nocturnal diarrhoea, fever, objective weight loss, anaemia, mass, raised calprotectin or new symptoms at an older age requires the appropriate urgent investigation pathway.
Continuing weight loss, food fear, an expanding exclusion list, social withdrawal or micronutrient deficiency requires dietetic and possibly eating-disorder assessment.
Investigation priorities
Exclude coeliac disease while the person eats adequate gluten, using IgA tTG and assay-appropriate alternatives in IgA deficiency.
Management branches
A patient attributes recurrent gastrointestinal or systemic symptoms to wheat or gluten.
- Document symptom pattern, current gluten exposure, family and autoimmune risk, immediate allergy features and organic red flags.
- Perform coeliac testing while gluten is consumed and refer positive or high-risk discordant cases; use the allergy pathway for rapid IgE-type reactions.
- Investigate bleeding, weight loss, anaemia, inflammation or nocturnal symptoms through the appropriate NICE or BSG pathway.
- Explain that diet response alone cannot yet distinguish gluten from other wheat components.