Of 100 people you see in clinic, one may have coeliac disease. The Coeliac Society report a list of approximately 5,000 active members, that is to say, members who are new or currently renewing membership annually, with coeliac disease in Ireland. However over 16,500 members have registered with the Society at one time or another. In 2006, a company called Nutricia Dietary Care, also maintaining a database of people using their gluten-free prescribable foods, reported approximately 12,000 people with the disease in Ireland on their database.

However, these numbers are just the tip of the coeliac iceberg. It is a significantly under-diagnosed disease – for each person diagnosed there are likely to be 5-10 people who remain un-diagnosed. Screening studies have shown the prevalence to be around 1 in 100 in Ireland, giving an actual estimated total of near to 45,000. This under-diagnosis has led to this disease being known as the silent disease.

Silence is not always golden

Like diabetes, by the time people are finally diagnosed with coeliac disease, they have often had the disease for many years. In children, the symptoms may be more classical (see below). However, in adults, whom are mainly diagnosed in their 40’s onwards, the symptoms are not always so obvious.

Hence, those un-diagnosed, may be going through life suffering symptoms such as repeated bloating, recurrent mouth ulcers, heartburn, alopecia, migraines, depression, fatigue or sub-fertility. The clinical impact of un-diagnosed Coeliac disease are far reaching and can include osteoporosis, anaemia, endocrine abnormalities, neurological dysfunction, infertility and low grade ill-health.

Classical symptoms of Coeliac Disease

• Steatorrhoea
• Diarrhoea
• Abdominal cramps
• Weight loss
• Bloating

Who should be tested?

We now know that coeliac disease can commonly manifest in atypical symptoms, leading the recent NICE clinical guidelines on Coeliac Disease (2009) to recommend health professional to offer serological testing to children and adults with any of the following signs and symptoms:

Signs and symptoms	Conditions
Chronic or intermittent diarrhoea	Autoimmune thyroid disease
Failure to thrive or faltering growth (in children)	Dermatitis herpetiformis
Persistent or unexplained gastrointestinal symptoms including nausea and vomiting	Irritable bowel syndrome
Prolonged fatigue (“tired all the time”)	Type 1 diabetes
Recurrent abdominal pain, cramping or distension	First-degree relatives with coeliac disease (parents, siblings or children)
Sudden or unexpected weight loss
Unexplained iron-deficiency anaemia, or other unspecified anaemia

The NICE guidelines also recommend health professionals to consider offering serological testing for coeliac disease to children and adults with any of the following conditions:

Addison’s disease	Microscopic colitis
Amenorrhoea	Persistent or unexplained constipation
Aphthous stomatitis (mouth ulcers)	Persistently raised liver enzymes with unknown cause
chronic thrombocytopenia purpura	Polyneuropathy
Dental enamel defects	Recurrent miscarriage
Depression or bipolar disorder	Reduced bone mineral density
Down’s syndrome	Sarcoidosis
Epilepsy	Sjögren’s syndrome
Low-trauma fracture	Turner syndrome
Lymphoma	Unexplained alopecia
Metabolic bone disease (such as rickets or osteomalacia)	Unexplained subfertility

How to test?

The gluten sensitive enteropathy is characterized by inflammation of the gut with or without structural damage. The structural damage may result in flattened villi, crypt proliferation and lymphocyte proliferation of the gut epithelium. As such the gold standard for diagnosis is a duodenal biopsy.

However, the serological test, tissue transglutaminase (tTG), is making diagnosis more accessible for hospitals and especially GPs. GPs can play an important role in diagnosing coeliac disease. Research has shown that when a GP suspected coeliac disease, the condition was 9 times more common (Collins et al, 2002) and that serological testing by GPs has resulted in a considerable increase in diagnosis rates in the Northern Ireland (Dickey et al, 2005).

The difficulty lies in the choice of further serological tests, should the tTG result come back equivocal. The NICE guidelines recommend the following serology be requested in the following sequence depending on results:

• Use IgA tissue transglutaminase (tTGA) as the first choice test
• Use IgA endomysial antibodies (EMA) testing if the result of the tTGA test is equivocal
• Check for IgA deficiency if the serology is negative
• use IgG tTGA and/or IgG EMA serological tests for people with confirmed IgA deficiency

As with any serological test, they need to be done in the light of a thorough medical history including family history as this is a genetically pre-disposed disease. Health professionals must inform clients (and their parents or carers, as appropriate) that testing for coeliac disease is only accurate if the client remains on a gluten containing diet prior and during the testing process. Clients should not start a gluten-free diet until a diagnosis of coeliac disease has been confirmed.

There are a number of useful guidelines available for the diagnosis and management of patients with coeliac disease.

European Society for the Study of Coeliac Disease (ESsCD)  Guideline for Coeliac Disease and Other Gluten-related Disorders Al-Toma A, Volta U, Auricchio R, et al | 14 Nov 2023 Recommendations in this summary are on serology, diagnosis, dietary management, follow up, slow responders and refractory CeD (RCeD), special issues, non-coeliac gluten sensitivity (NCGS), and CeD-related skin and orodental disorders. For more detail on each of these areas, refer to the full guideline.

The  NICE Guidelines on Coeliac Disease Recognition and assessment of coeliac disease also provide a care pathway which outlines a diagnostic algorithm.

The BSG (2014) produced  guidelines  for the diagnosis and treatment of adults with coeliac disease entitled BSG guideline for the diagnosis and management of CD in adults.