What is Coeliac Disease?
Coeliac disease is a permanent, lifelong inflammatory disease of the upper small
intestine and result from gluten ingestion in genetically susceptible individuals.
This causes damage to the lining of the intestines. This leads to poor absorption
of important nutrients including iron, folic acid, calcium, and fat-soluble vitamins.
Gluten is a protein found mainly in wheat and to a lesser extent in rye, oats and
barley. Hence the alternative name for the condition is Gluten-sensitive Enteropathy.
Coeliac Disease is closely related to dermatitis herpetiformis. In dermatitis herpetiformis,
skin rash and a similar small intestinal enteropathy to that of coeliac disease
are typically present, and both respond to withdrawal of gluten.
Is Coeliac an Autoimmune disease?
Coeliac disease is associated with a variety of autoimmune disorders. Increased
incidence of Rheumatoid Arthritis, diabetes mellitus, autoimmune thyroid disease,
sarcoidosis, vasculitis and pulmonary fibrosis has been reported in coeliac patients.
The prevalence of coeliac disease among children with diabetes (IDDM) is 50 times
more likely than chance. IgA deficiency is 10 times more common in coeliac patients
than in the general population. Patients with coeliac disease and selective IgA
deficiency often have circulating antibodies to food proteins; they also have circulating
immune complexes, suggesting that absence of an intestinal barrier might allow the
absorption of antigenic material from the gut. Antibodies to some antigens might
cross react with the host's self-components and might indirectly produce autoimmune
How common is Coeliac?
Studies show coeliac to be a more common disorder than previously thought, possibly
affecting up to 1 in 300 of the general population. The majority of patients finally
diagnosed in adulthood usually in the 30-45 year age group. As a result, many other
cases may not be discovered and are often falsely diagnosed as Irritable bowel Syndrome
(IBS). In fact only about one third of cases are ever diagnosed as coeliac disease
and appropriately treated with a gluten-free diet. Untreated coeliac disease is
associated with long-term risks such as osteoporosis and gastrointestinal malignancy.
Does it run in families?
Yes, it certainly can. The incidence in first-degree relatives (parents, siblings)
is about 10-15% if a family member (parent or sibling) has Coeliac Disease.
What is the difference between Coeliac Disease & wheat Allergy?
Although the precise cause of coeliac is unknown, T cells may play a central role.
A T cell-mediated or Type 4 (Delayed Hypersensitivity Immune response) to gluten
is likely to be the major cause of the gut lesions and increased permeability to
gluten and other foods. T cells may react with tissue glutaminase (the principal
component of the endomysium auto antigen) and set in motion a series of inflammatory
events that results in the classical coeliac mucosal lesion. Wheat Allergy, on the
other hand, is a Type 1 (Immediate Hypersensitivity Immune response) where wheat
protein causing excessive production of IgE antibodies. These IgE antibodies sit
on mast cells & when the intestine comes in contact with wheat, they bind to the
IgE antibodies & cause the mast cell to release histamine & other mediators. These
excessive IgE antibodies to wheat can be measured in the blood by doing a RAST or
a Skin Prick Test. This is usually seen in an atopic individual & commonly associated
with eczema. In wheat allergy the individual will only react to wheat, whereas in
coeliac they react to all gluten-containing cereals such as wheat, oats, barley
What are the symptoms?
Most gastroenterologists recognise that Samuel Gee's description of coeliac disease
in 1888 is now an uncommon presentation – but most general practitioners' image
of coeliac disease is still of this classic form. Recent advances, driven by Antibody
blood tests have lead to the realisation that clinically overt cases represent only
a small proportion of patients with the disorder. The classical symptoms are malabsorption
of food and chronic diarrhoea associated with anaemia, failure to grow, abdominal
distension, offensive bulky stool and mouth ulcers. This is usually seen in infants
less than 2 years of age, usually when they are weaned off milk onto solids. This
fulminant presentation is now uncommon, and as paediatric patients tend to present
at a later age (median 4 years), features such as loss of appetite and a short stature
Intestinal symptoms may be absent in adults with coeliac disease. In adults, the
disease often presents in a milder form, and therefore easily missed – especially
with non-specific symptoms such as fatigue, vague abdominal pains, intermittent
diarrhoea and slight anaemia. The most likely presentation is a combination of microcytic
anaemia, past or present, a family history of the disease, and feeling tired all
How is coeliac disease diagnosed?
Small intestine biopsy
The "gold standard" for diagnosing coeliac disease is still a biopsy of the small
intestine. This can be done with or without sedation. A specimen is taken from the
distal end of the duodenum via an upper gastrointestinal endoscopy. The specimen
is scrutinized microscopically for flattening of the normal villi (folds) in the
lining of the intestine as in this diagram.
The coeliac screening blood test measures antibodies in the blood to gluten or gliaden
in the diet (ant gliadin antibody) and the damaged Endomysial muscle of the bowel
With the advent of the Endomysial antibody test, blood (serological) diagnosis of
coeliac disease has come to the forefront. Endomysial antibodies are closely associated
with gluten sensitive disease, and in appropriate clinical setting coeliac disease
can be diagnosed with 100% specificity. As the assay depends on the detection of
IgA antibodies, the endomysial antibody test is obviously negative in individuals
with IgA deficiency (which is 10 times more common in coeliac disease), but is also
negative in a proportion of other patients; however a sensitivity of 86% or greater
has been observed. Assays for antigliadin antibody can help in this situation, enabling
almost all patients to be identified.
Screening for Coeliac Disease
It is useful to screen first-degree relatives of known coeliacs, those presenting
with vague symptoms, or other at-risk patients.
Both Antigliadin antibody & anti-endomysial antibody tests are usually done along
with IgA levels. The anti-endomysial test is more reliable, and is useful in screening
of undiagnosed Coeliacs. People who have already commenced a gluten free diet will
not be suitable for this test. Advantages of the blood screening are that it is
non-invasive, and relatively inexpensive. Disadvantages are that it is not diagnostic.
A positive test at this stage still requires a small bowel biopsy.
How is Coeliac Disease Managed?
Those that contain gluten
Wheat, wheatmeal, wheat germ, rye, oats, oatmeal, oat bran, barley, triticale, pasta,
semolina, farina, bread, biscuits, batter, crumbs, malt, malt flavouring, malt extract.
Those that may contain gluten (depending on source)
Modified starch, thickening agents (1400 -1450), maltodextrin, dextrin, dextrose,
hydrolysed protein, glucose, glucose syrup, caramel (colour), foods containing component
ingredient (eg baking powder).
Those that are definitely gluten free
Rice, rice bran, rice flour, corn, maize flour, maize meal, polenta, potato flour,
buckwheat, arrowroot, chickpea flour, pea flour, Soya flour, lentils, lentil flour,
sago, tapioca, amaranth.