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This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.
The Bottom Line
- Autoimmune reaction to gluten (wheat, barley, rye) → small bowel villous atrophy
- Screen with total IgA + tissue transglutaminase IgA (tTG-IgA). Patient MUST be eating gluten for ≥6 weeks before testing
- Gold standard diagnosis: duodenal biopsy (D2) showing villous atrophy, crypt hyperplasia, intraepithelial lymphocytosis (Marsh classification)
- Treatment: lifelong strict gluten-free diet — this is the ONLY treatment
- Associated conditions: type 1 diabetes, thyroid disease, dermatitis herpetiformis, IgA deficiency
- Untreated coeliac increases risk of enteropathy-associated T-cell lymphoma (EATL) and small bowel adenocarcinoma
Overview
Coeliac disease is an autoimmune condition where ingestion of gluten triggers an immune-mediated inflammatory response in the small intestinal mucosa, leading to villous atrophy and malabsorption. Gluten is found in wheat, barley, and rye. The condition has a strong genetic component with >95% of patients carrying HLA-DQ2 and the remainder HLA-DQ8. It is one of the commonest autoimmune conditions, affecting approximately 1% of the UK population, though the majority remain undiagnosed.
Epidemiology
Prevalence is approximately 1% in the UK, though only ~30% are currently diagnosed. More common in females (2:1). Strong association with other autoimmune conditions — particularly type 1 diabetes (5–10% have coeliac), autoimmune thyroid disease, and IgA deficiency (2–3% of coeliac patients). Family history confers 10% risk in first-degree relatives. Can present at any age, from weaning in infancy to elderly. The clinical spectrum ranges from classic malabsorption to subtle symptoms (fatigue, anaemia) to entirely asymptomatic.
Clinical Features
Symptoms
Chronic diarrhoea (may be steatorrhoea — pale, bulky, foul-smelling)
Bloating and abdominal discomfort
Fatigue (often the predominant symptom in adults)
Weight loss
Iron deficiency anaemia unresponsive to oral iron (unexplained anaemia is a common presentation)
Mouth ulcers
Failure to thrive and growth failure in children
Dermatitis herpetiformis: intensely itchy vesicular rash on extensor surfaces
Signs
May be clinically normal
Pallor (anaemia)
Angular stomatitis, glossitis (B12/iron/folate deficiency)
Low BMI, muscle wasting (severe malabsorption)
Abdominal distension
Dermatitis herpetiformis (grouped vesicles on elbows, knees, buttocks)
Signs of osteomalacia (proximal myopathy, bone pain) from vitamin D malabsorption
Investigations
First-line
Total IgA + tTG-IgA antibodyFirst-line serological test. Must be eating gluten-containing diet for ≥6 weeks before testing. Check total IgA to exclude IgA deficiency (false negative)
If IgA deficientRequest IgG-based tests: tTG-IgG or deamidated gliadin peptide (DGP) IgG
Second-line
Duodenal biopsy (OGD)Gold standard — take ≥4 biopsies from D2 (and D1). Histology: villous atrophy, crypt hyperplasia, increased intraepithelial lymphocytes (Marsh 3). Patient must still be eating gluten at time of biopsy
Endomysial antibody (EMA)Highly specific (>99%) — used as confirmatory test if tTG is equivocal
Specialist
HLA-DQ2/DQ8 typingHigh negative predictive value — if absent, coeliac is effectively excluded. Useful if diagnosis uncertain or patient already on GFD
DEXA scanAssess bone mineral density — coeliac is a risk factor for osteoporosis
Bloods for deficienciesIron, B12, folate, calcium, vitamin D, ferritin, clotting (vitamin K) — guide replacement therapy
Management
NICE NG20 (Coeliac disease), 20151
Lifelong strict gluten-free diet (GFD)
- Remove ALL wheat, barley, rye from diet — oats are tolerated by most but should be introduced cautiously
- This is the ONLY treatment — there are no drugs that treat coeliac disease
- Dietitian referral is essential at diagnosis
- Coeliac UK membership provides support and food directory
- GFD prescriptions available on NHS (gluten-free bread, pasta, flour)
2
Nutritional replacement
- Iron, B12, folate supplementation as needed
- Calcium and vitamin D (assess bone density with DEXA)
- Monitor haematinics and nutritional markers at follow-up
3
Follow-up and monitoring
- Repeat tTG-IgA at 6–12 months — should normalise on GFD (confirms adherence)
- Annual review: symptoms, dietary adherence, repeat serology, bloods for nutritional deficiencies
- DEXA scan at diagnosis if risk factors; repeat based on results
- No routine cancer surveillance required if GFD adherent
4
Refractory coeliac disease
- Persistent symptoms and villous atrophy despite strict GFD for ≥12 months
- Confirm genuine adherence (dietitian review, check for inadvertent gluten exposure)
- Type 1 (polyclonal T cells): may respond to immunosuppression (budesonide, azathioprine)
- Type 2 (monoclonal T cells): pre-lymphomatous — requires specialist haematology input
Complications
- Enteropathy-associated T-cell lymphoma (EATL): Rare but serious — risk reduced with strict GFD adherence
- Small bowel adenocarcinoma: Increased risk in untreated coeliac
- Osteoporosis: From calcium and vitamin D malabsorption — DEXA scan at diagnosis
- Nutritional deficiencies: Iron, B12, folate, fat-soluble vitamins (A, D, E, K)
- Subfertility and adverse pregnancy outcomes: Recurrent miscarriage, IUGR — resolves with GFD
- Hyposplenism: Functional hyposplenism — consider pneumococcal vaccination
- Dermatitis herpetiformis: Skin manifestation — also responds to GFD (± dapsone for acute relief)
UKMLA Exam Tips
- 1Patient must be eating gluten for ≥6 WEEKS before serology and biopsy — otherwise false negatives
- 2Always check TOTAL IgA alongside tTG-IgA — 2–3% of coeliac patients are IgA deficient (false negative tTG)
- 3Unexplained iron deficiency anaemia, especially if not responding to oral iron → test for coeliac disease
- 4Dermatitis herpetiformis = coeliac disease of the skin. Intensely itchy vesicles on extensor surfaces. Treat with GFD ± dapsone
- 5HLA-DQ2/DQ8 negative effectively RULES OUT coeliac — useful when patient already on GFD and you cannot do standard serology
- 6Type 1 diabetes + unexplained GI symptoms → screen for coeliac (5–10% prevalence in T1DM)
practicetest your knowledge on coeliac diseaseApply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — gastroenterology and beyond.
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