Coeliac disease is a serious autoimmune condition in which eating gluten — a protein found in wheat, barley, and rye — triggers an immune response that damages the small intestine lining. It affects approximately 1 in 100 people in the UK, yet only around 36% of those with coeliac disease have been diagnosed — an estimated 500,000 people are living with it undiagnosed. The only treatment is a strict, lifelong gluten-free diet.
What Is Coeliac Disease?
Coeliac disease is not a food allergy or intolerance — it is an autoimmune condition. When someone with coeliac disease eats gluten, their immune system attacks the villi — tiny finger-like projections that line the small intestine and absorb nutrients. Over time, this causes the villi to flatten (villous atrophy), dramatically reducing the intestine’s ability to absorb nutrients. This leads to malabsorption of iron, calcium, folate, vitamins B12 and D, and other essential nutrients.
Symptoms of Coeliac Disease
Coeliac disease is sometimes called “the great pretender” — its symptoms are highly variable and frequently misattributed to IBS, which delays diagnosis by an average of 13 years in the UK.
Digestive Symptoms
- Diarrhoea — often loose, pale, fatty, and difficult to flush (steatorrhoea)
- Abdominal pain and cramping
- Bloating and wind
- Nausea and vomiting
- Constipation — less common but can occur
- Indigestion
Non-Digestive (Extra-Intestinal) Symptoms
- Fatigue and anaemia — from iron, folate, or B12 deficiency; the most common presentation in adults
- Mouth ulcers — recurrent aphthous ulcers
- Dermatitis herpetiformis (DH) — an intensely itchy skin rash with blisters, typically on the elbows, knees, buttocks, and back; the skin manifestation of coeliac disease
- Bone pain and osteoporosis — from calcium and vitamin D malabsorption
- Neurological symptoms — peripheral neuropathy, ataxia (gluten ataxia), difficulty walking
- Infertility and recurrent miscarriage — undiagnosed coeliac disease is a treatable cause of infertility
- Joint pain
- Depression and anxiety
- Delayed puberty and growth failure — in children
- Liver abnormalities — elevated liver enzymes on blood tests
Causes and Risk Factors
Coeliac disease requires three factors: a genetic predisposition, exposure to gluten, and an environmental trigger. Around 99% of people with coeliac disease carry the HLA-DQ2 or HLA-DQ8 gene variants, though 25% of the general population carry these genes without developing coeliac disease. Risk factors include:
- Family history — first-degree relatives of someone with coeliac disease have a 10% risk
- Type 1 diabetes — 10% of people with Type 1 also have coeliac disease
- Down’s syndrome — 5–10% have coeliac disease
- Turner syndrome, Williams syndrome
- Autoimmune thyroid disease
Diagnosis
Crucially: you must be eating gluten regularly (at least 1–2 slices of bread equivalent daily for 6 weeks) before any testing — otherwise results will be falsely negative. Do not start a gluten-free diet before testing.
Step 1: Blood Tests
- Total IgA and IgA tissue transglutaminase antibodies (tTGA) — the primary screening test; high sensitivity and specificity; total IgA must be checked alongside (IgA deficiency, present in ~2.5% of people with coeliac, causes false-negative tTGA)
- IgA endomysial antibodies (EMA) — highly specific; used as confirmatory test
- IgG deamidated gliadin peptide (DGP) — used when IgA deficiency is present
Step 2: Duodenal Biopsy (Gastroscopy)
A gastroscopy (endoscopy) with biopsies of the duodenum (small intestine) is required to confirm the diagnosis in adults. Biopsies are taken from at least four sites and examined under a microscope for villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes — characteristic findings of coeliac disease (Marsh classification grades 1–4).
Updated NICE guidance (NG20, 2015): In adults with strongly positive tTGA (≥10× upper limit of normal) who also have positive EMA on a second blood sample, a biopsy may not be required. Discuss with your gastroenterologist.
Treatment: The Gluten-Free Diet
The only effective treatment for coeliac disease is a strict, lifelong gluten-free diet. Even small amounts of gluten — sometimes called “crumbs” — can trigger immune reactions and intestinal damage. This means:
Foods to Avoid
- Wheat (including spelt, kamut, durum, semolina, farro)
- Barley (including malt, malt vinegar, beer)
- Rye
- Standard oats — most people with coeliac can tolerate uncontaminated, “pure” oats (Coeliac UK certified), but some cannot; introduce cautiously after diagnosis under medical supervision
Naturally Gluten-Free Foods
- Rice, potatoes, maize/corn, millet, buckwheat, quinoa, sorghum, tapioca
- All unprocessed meat, fish, eggs, dairy, fruit, and vegetables
- Legumes, nuts, and seeds (unprocessed)
NHS Gluten-Free Foods on Prescription
People with coeliac disease in England can receive certain gluten-free staples on NHS prescription — including gluten-free bread, flour, pasta, and cereals. This is particularly important for those on low incomes. Contact your GP to discuss what is available in your area (provision varies by CCB).
Cross-Contamination
Cross-contamination is a serious concern. Use separate toasters, chopping boards, and cooking utensils. Butter tubs shared with bread crumbs must be avoided. Eating out requires careful communication with restaurant staff — ask about dedicated fryers and preparation areas. The Coeliac UK “Crossed Grain” symbol on food packaging indicates a product meets strict gluten-free standards (<20 ppm gluten).
Follow-Up and Monitoring
After diagnosis, the NHS recommends:
- Annual review with your GP or dietitian
- Repeat tTGA blood test at 6 and 12 months (should fall on a gluten-free diet)
- DEXA bone density scan at diagnosis (osteoporosis risk from calcium malabsorption)
- Nutritional blood tests: iron, ferritin, B12, folate, vitamin D, calcium
- Dietitian referral for gluten-free diet education — strongly recommended
- Pneumococcal vaccination — splenic dysfunction is a rare complication of coeliac disease
Support
Coeliac UK (coeliac.org.uk) — helpline: 0333 332 2033; membership gives access to the app with 350,000+ food and drink products checked, restaurant guides, and local support groups. An invaluable resource for anyone newly diagnosed.
This article is for informational purposes only. Do not start a gluten-free diet before being tested — this will prevent an accurate diagnosis. See your GP if you have persistent digestive symptoms or are concerned about coeliac disease.
Related Health Guides on YourHealthXpert
Explore these related NHS-aligned health guides:
- IBS Guide — Coeliac disease and IBS share overlapping symptoms; learn how to tell them apart and understand NHS diagnostic criteria.
- Crohn’s Disease Guide — Both Crohn’s and coeliac disease are autoimmune gut conditions with some shared dietary considerations under NHS care.
- Bowel Cancer Guide — Undiagnosed coeliac disease slightly increases bowel cancer risk; understand the NHS screening programme and warning signs.
- Osteoporosis Guide — Untreated coeliac disease causes calcium malabsorption, increasing osteoporosis risk significantly; learn the NHS bone health approach.
- Liver Disease (NAFLD) Guide — Coeliac disease is associated with elevated liver enzymes and liver complications; understand the autoimmune connection.
- Rheumatoid Arthritis Guide — As autoimmune conditions, coeliac and RA can co-occur; learn about the NHS approach to managing multiple autoimmune diagnoses.