Key Facts

Coeliac disease is a systemic autoimmune disorder triggered by gluten (prolamin proteins in wheat, barley, and rye) in genetically predisposed individuals. It causes chronic small bowel inflammation and villous atrophy leading to malabsorption. It is one of the most common chronic conditions in children.

Epidemiology

Prevalence is approximately 1% (1 in 100) in the UK and Europe. Many cases are undiagnosed — the 'coeliac iceberg'. Peak presentation in children is at 1-3 years (after gluten introduction) and again in later childhood/adolescence. Female:male ratio approximately 2:1. First-degree relatives have a 10% risk.

Aetiology

• Genetic: HLA-DQ2 (present in ~95%) or HLA-DQ8 (~5%) is necessary but not sufficient
• Environmental trigger: Dietary gluten (gliadin peptides from wheat, hordeins from barley, secalins from rye)
• Additional factors: Timing of gluten introduction, GI infections, gut microbiome composition

Pathophysiology

Gliadin peptides resist complete digestion and cross the intestinal epithelium. Tissue transglutaminase (tTG) deamidates gliadin → enhanced binding to HLA-DQ2/DQ8 on antigen-presenting cells → CD4+ T-cell activation → release of pro-inflammatory cytokines (IFN-γ) → crypt hyperplasia and villous atrophy. Intraepithelial lymphocyte infiltration is an early feature. Villous atrophy in the proximal small bowel reduces absorptive surface area → malabsorption of iron, folate, calcium, fat-soluble vitamins.

Classic Presentation (toddlers)

• Chronic diarrhoea, steatorrhoea
• Abdominal distension and pain
• Failure to thrive, weight loss
• Irritability, anorexia
• Muscle wasting, buttock wasting

Non-classic Presentation (older children)

• Iron deficiency anaemia unresponsive to oral iron
• Short stature, delayed puberty
• Recurrent mouth ulcers (aphthous stomatitis)
• Dental enamel defects
• Fatigue, poor school performance
• Arthralgia

Associated Conditions

• Dermatitis herpetiformis (intensely itchy vesicular rash on extensor surfaces)
• Type 1 diabetes (~10% have coeliac disease)
• Autoimmune thyroid disease
• IgA deficiency (2-3% of coeliac patients are IgA deficient — serology may be falsely negative)

Red Flags

• Persistent failure to thrive with GI symptoms — investigate for coeliac disease
• Iron deficiency anaemia in a child without obvious cause
• Any child with type 1 diabetes, Down syndrome, or Turner syndrome should be screened

Bedside

• Growth assessment: Plot height, weight, BMI on centile charts
• Clinical examination: Abdominal distension, muscle wasting, pallor, mouth ulcers

Bloods

• Total IgA + IgA-tTG antibodies: First-line screening (NICE NG20). If IgA deficient, request IgG-tTG or IgG deamidated gliadin peptide (DGP)
• IgA-endomysial antibodies (EMA): High specificity; used as confirmatory test
• FBC: Iron deficiency anaemia (microcytic), folate deficiency (macrocytic)
• Ferritin, folate, vitamin B12: Assess nutritional deficiencies
• Calcium, vitamin D, phosphate: Malabsorption of calcium and vitamin D
• LFTs: Mildly elevated transaminases occur in ~40% and normalise on GFD
• HLA-DQ2/DQ8: Useful for exclusion — virtually 100% negative predictive value

Imaging

• Not routinely required; DEXA scan if concerns about bone mineral density in older children

Special Tests

• Duodenal biopsy (OGD): Gold standard — at least 4 biopsies from D2 + 1 from bulb; Marsh classification:
  • Marsh 0: Normal
  • Marsh 1: Increased intraepithelial lymphocytes (>25 per 100 enterocytes)
  • Marsh 2: Crypt hyperplasia
  • Marsh 3a/b/c: Partial to total villous atrophy
• ESPGHAN no-biopsy pathway (children): If tTG >10× ULN AND positive EMA on separate sample AND HLA-DQ2/DQ8 positive AND symptomatic → biopsy may be omitted

Non-pharmacological

• Strict lifelong gluten-free diet (GFD): Exclude wheat, barley, rye; oats tolerated by most but introduce cautiously
• Dietitian referral: Essential at diagnosis for GFD education, nutritional adequacy, label reading
• Coeliac UK membership: Practical support, food directory, social support
• School/nursery education: Ensure awareness of dietary needs

Pharmacological

• Vitamin and mineral supplementation: Iron, folate, calcium, vitamin D as guided by blood results
• Calcium/vitamin D: If deficient — cholecalciferol 400-1000 IU daily
• Pneumococcal vaccination: Recommended for all coeliac patients due to functional hyposplenism (Green Book)
• Annual influenza vaccine: Recommended

Surgical/Interventional

• Not applicable

Referral Criteria

• All children with positive serology — paediatric gastroenterology for confirmation and dietary management
• Failure to respond to GFD after 6-12 months — reconsider diagnosis, assess compliance
• Persistent symptoms despite strict GFD — consider refractory coeliac disease (rare in children)

• Excellent prognosis with strict GFD adherence — symptoms typically improve within weeks, serology normalises within 6-12 months
• Villous atrophy: Takes 6-24 months to recover fully on GFD
• Non-adherence associated with increased risk of osteoporosis, iron deficiency, lymphoma (rare in children)
• Growth: Catch-up growth occurs in most children after GFD initiation
• Lymphoma risk: Small cell lymphoma of the small bowel — risk increased with non-compliance; absolute risk remains very low in childhood
• Quality of life: Social challenges with dietary adherence, particularly in adolescence

Marsh Classification

Who to Screen (NICE NG20)