Coeliac Disease .

Coeliac disease is a common autoimmune condition triggered by gluten that causes small bowel inflammation and malabsorption.
It often presents subtly and is frequently missed.

This guide focuses on when to suspect it, how to investigate properly, and what doctors should actually do in everyday NHS practice.

What is coeliac disease?

Coeliac disease is:

An autoimmune reaction to gluten causing inflammation and damage to the small intestine.

This leads to:

  • Malabsorption
  • Nutritional deficiencies
  • Long-term complications if untreated

It is not just a dietary intolerance — it is an autoimmune disease.

How does it present?

Presentation is often non-classical.

Classic symptoms (less common now):

  • Chronic diarrhoea
  • Steatorrhoea
  • Weight loss
  • Bloating

More common real-life presentations:

  • Iron deficiency anaemia
  • Fatigue
  • Low B12/folate
  • Osteoporosis
  • Recurrent mouth ulcers
  • Unexplained LFT abnormalities
  • “IBS-type” symptoms

Many patients have no GI symptoms at all.

On the ward or clinic, always ask

Could this unexplained anaemia or chronic symptom be coeliac disease?

Because:

Iron deficiency anaemia with no obvious source = coeliac until proven otherwise

This is a very common exam and real-life scenario.

Common risk factors (think practically)

Higher risk groups:

  • Family history
  • Type 1 diabetes
  • Autoimmune thyroid disease
  • Down syndrome
  • Other autoimmune conditions

If someone has one autoimmune condition → think of others.

Typical blood test clues

You might see:

  • Iron deficiency anaemia
  • Low ferritin
  • Low B12 or folate
  • Low vitamin D
  • Low albumin
  • Mildly raised ALT

Pattern:

Malabsorption rather than inflammation

Key investigations (what juniors should actually order)

Step 1 – Serology:

  • tTG-IgA (first-line test)
  • Total IgA (to exclude IgA deficiency)

If IgA deficient:

  • Use IgG-based tests

Step 2 – Endoscopy:

  • OGD with duodenal biopsies
  • Confirms diagnosis

Important:

Do NOT start gluten-free diet before testing
This can give false negatives.

First priority = test before dietary advice

A common mistake:
Patients self-start gluten-free diets before testing → makes diagnosis difficult.

Always:

  • Test first
  • Confirm diagnosis
  • Then dietary changes

Management (real-world practice)

Main treatment:

Lifelong strict gluten-free diet

This:

  • Improves symptoms
  • Normalises bloods
  • Reduces cancer risk
  • Prevents complications

Also:

  • Dietitian referral
  • Replace deficiencies (iron, B12, vitamin D, calcium)
  • Monitor bone health

No medication usually required.

Complications you should know

If untreated:

  • Osteoporosis
  • Infertility
  • Persistent anaemia
  • Neuropathy
  • Lymphoma (rare but important)
  • Other autoimmune disease

Early diagnosis prevents most of these.

When to escalate or refer

Refer to gastro if:

  • Positive serology
  • Persistent unexplained anaemia
  • Weight loss
  • Severe malnutrition
  • Diagnostic uncertainty

Urgent referral if:

  • Severe weight loss
  • Red flag symptoms (bleeding, severe pain, obstruction)

Common mistakes juniors make

  • Not testing for coeliac in iron deficiency anaemia
  • Advising gluten-free diet before testing
  • Assuming IBS without investigation
  • Ignoring low ferritin
  • Forgetting total IgA

Coeliac disease is often missed because symptoms are vague.

Take-home concept

Coeliac disease often hides behind anaemia and fatigue rather than diarrhoea.
Think of it early, test properly, and confirm before changing diet.