Summary

Coeliac disease is a chronic autoimmune enteropathy triggered by dietary gluten in genetically susceptible individuals (HLA-DQ2/DQ8). It causes inflammation and villous atrophy in the small intestine, leading to malabsorption. The condition affects approximately 1% of the population, though many cases remain undiagnosed. Symptoms range from classic diarrhoea and weight loss to atypical presentations including anaemia, fatigue, and osteoporosis. Diagnosis requires positive serology (tissue transglutaminase IgA) followed by duodenal biopsy. Treatment is a strict lifelong gluten-free diet.

Key Facts

• Definition: Autoimmune enteropathy triggered by gluten in HLA-DQ2/DQ8-positive individuals
• Prevalence: ~1% of population; many undiagnosed
• Genetics: HLA-DQ2 (95%) or HLA-DQ8 (5%) required but not sufficient
• Key Serology: tTG-IgA (first-line); remember to check total IgA
• Biopsy: Villous atrophy + crypt hyperplasia + increased IELs (Marsh classification)
• Treatment: Strict lifelong gluten-free diet (GFD)

Clinical Pearls

"Must Be Eating Gluten": Serology AND biopsy are only valid if the patient is currently eating gluten. Do NOT recommend a GFD before investigations are complete — this can cause false negatives and diagnostic difficulty.

IgA Deficiency Trap: 2-3% of coeliac patients have IgA deficiency. If total IgA is low, tTG-IgA will be falsely negative. Request IgG-based tests (tTG-IgG or DGP-IgG).

Think Beyond Gut: Many patients present with extraintestinal manifestations — unexplained iron deficiency anaemia, osteoporosis, elevated transaminases, or neurological symptoms — rather than classic GI symptoms.

Why This Matters Clinically

Coeliac disease is underdiagnosed because many patients have non-classic presentations. Untreated disease leads to serious complications including osteoporosis, infertility, and increased lymphoma risk. A correct diagnosis enables effective treatment with a gluten-free diet, improving quality of life and preventing complications.

Structured Approach

General:

• Nutritional status (BMI, muscle mass)
• Signs of anaemia (pallor, tachycardia)
• Dermatological examination

Abdominal Examination:

• Distension
• Tenderness
• Masses (rare — suggests complication)

Special Tests

Natural History

With strict adherence to a gluten-free diet, most patients achieve complete symptom resolution and mucosal healing. Untreated coeliac disease leads to progressive malnutrition and increased risk of serious complications including lymphoma.

Outcomes with Treatment

Prognostic Factors

Good Prognosis:

• Strict dietary compliance
• Younger age at diagnosis
• Classic presentation (responds well to GFD)
• Serology and histology normalise

Poor Prognosis:

• Refractory coeliac disease (Type 2)
• Older age at diagnosis
• Severe malnutrition at presentation
• Non-compliance with GFD

Key Guidelines

1. NICE NG20: Coeliac Disease (2015) — Comprehensive UK guidance on recognition, diagnosis, and management.

2. BSG Guidelines (2014) — British Society of Gastroenterology guidance on testing, biopsy, and follow-up.

Landmark Studies

Ludvigsson et al. (2013) — Lancet

• Large population-based study
• Key finding: Coeliac disease associated with increased mortality, driven by malignancy
• Clinical Impact: Emphasises importance of diagnosis and treatment

Leffler & Schuppan (2010) — Update on Coeliac Disease

• Comprehensive review of pathophysiology and management
• Clinical Impact: Established modern understanding of disease mechanism

Evidence Strength

What is Coeliac Disease?

Coeliac disease is a condition where your immune system reacts abnormally to gluten — a protein found in wheat, barley, and rye. When you eat gluten, your immune system attacks the lining of your small intestine, damaging it and making it difficult to absorb nutrients from food.

Why does it matter?

Without treatment, coeliac disease can cause serious problems:

• Anaemia (low iron levels)
• Weak bones (osteoporosis)
• Tiredness and feeling unwell
• Long-term, slightly increased risk of some cancers

The good news is that treatment is very effective. With a gluten-free diet, the gut heals and most people feel completely better.

How is it treated?

1. Gluten-free diet for life: You need to completely avoid wheat, barley, and rye. This means avoiding most breads, pasta, cereals, cakes, and biscuits unless they're specifically gluten-free.

2. Safe foods: Rice, potatoes, corn, quinoa, meat, fish, eggs, fruit, and vegetables are naturally gluten-free.

3. Dietitian support: You'll be referred to a dietitian who will teach you how to read food labels and avoid hidden gluten.

4. Supplements: You may need iron, vitamin D, or calcium supplements initially if you have deficiencies.

5. Prescriptions: In the UK, you can get some gluten-free staples (bread, flour, pasta) on prescription.

What to expect

• Symptoms often improve within weeks of starting a gluten-free diet
• Complete gut healing can take 1-2 years
• Annual blood tests and check-ups to make sure you're staying healthy
• You'll need to follow the diet for life — even small amounts of gluten can cause damage

When to seek help

See a doctor if:

• Symptoms don't improve on gluten-free diet
• You're losing weight unexpectedly
• You have new or worsening symptoms
• You're struggling to follow the diet