Coeliac disease (coeliac sprue or gluten allergy)

What is coeliac disease?

Term watch

Coeliac disease is also known as gluten enteropathy or coeliac sprue.

Coeliac disease is a lifelong autoimmune condition, which is a multi-system disorder diagnosed by endoscopy with biopsy, of the small intestine (bowel).

Gluten is predominantly a mixture of two proteins, gliadin and glutenin. It is found in wheat, barley and rye. When combined with water gluten becomes sticky and forms the familiar texture of dough.

In coeliac disease, gluten causes the immune system to produce antibodies that attack the delicate lining of the bowel, which is responsible for absorbing nutrients and vitamins from food.

Coeliac disease can be diagnosed at any age and can be diagnosed in babies after weaning, when cereals containing gluten are first introduced into the diet. However, the most common age of diagnosis is currently between 40 and 60 years old.

The symptoms can be subtle, and you may feel unwell for some time for no reason before the diagnosis is made.

If left untreated, coeliac disease can lead to anaemia, low bone density, osteoporosis and, rarely, some forms of gut cancer.

Avoiding all food that contains gluten generally results in the improvement, or even disappearance, of damage to the bowel lining. However, the damage will start again if gluten is re-introduced into the diet.

How does gluten damage the bowel?

Healthy villi of the small intestine (as seen under the microscope).

Damaged villi of the small intestine.

Villi completely destroyed by the immune system. All pictures courtesy of Prof PJ Ciclitira.

The small bowel contains villi, which are tiny finger-like projections that are only visible under a microscope.

They provide a large surface area over which we absorb nutrients such as folic acid, iron and calcium.

If you have coeliac disease, a reaction occurs when gluten comes into contact with the lining of the small bowel.

The villi are attacked by the immune system and become inflamed and flattened, as seen in the pictures above.

This results in nutrients from food going down the gut without being absorbed (malabsorption), leading to diarrhoea, vitamin and mineral deficiencies, anaemia and thin bones (osteporosis).

Who is at risk?

It used to be thought that coeliac disease affected about 1 in 1500 people. More accurate diagnosis through blood tests has shown that the condition affects 1 per cent of people across Europe. Coeliac disease affects all ethnic groups and is common not just in Europe, but also in South Asia, the Middle East, North West and East Africa and South America.

Coeliac disease is more common in women than men.

Coeliac disease is associated with other conditions. People with Type 1 diabetes, and thyroid problems have an increased chance of developing coeliac disease.

The risk of coeliac disease is increased by a family history of the condition. Coeliac disease occurs in people who are genetically prone to it.

If you have a parent, sibling or child with coeliac disease, you have a 10 per cent chance of also developing it. In identical twins, if one twin has coeliac disease, the chance of the other twin developing coeliac disease is more than 70 per cent.

What are the symptoms?

Term watch

Villi are finger like projections in the gut. They help the body to absorb nutrients from the food we eat.

Coeliac disease has many and varied symptoms, and symptoms in adults may be different to those in children. Symptoms do not appear until gluten-containing foods (bread, cereal) are introduced into the diet.

Childhood symptoms

In childhood: poor appetite, irritability and a failure to thrive are usually the first symptoms.

• Poor appetite, irritability and a failure to gain weight are usually the first symptoms.
• Pale, bulky stools that smell nasty.
• Vomiting and diarrhoea, which can lead to a wrong diagnosis of gastroenteritis.
• Swollen stomach.
• Arm and leg muscles may become wasted and thin.

Adult symptoms

In adults symptoms may include:

• weight loss with pale, offensive diarrhoea
• constipation
• abdominal bloating with wind.

However, adults with coeliac disease may not have any of these bowel symptoms. They approach their doctor because of:

• extreme tiredness
• anaemia
• depression
• bone pain and sometimes even fractures – which are due to thinning of the bones
• ulcers in the mouth
• a blistering, itchy skin rash mostly on the elbows and knees, called dermatitis herpetiformis
• recurrent miscarriages.

More recent research suggests that loss of balance (ataxia) and tingling in the hands and feet (neuropathy) are neurological symptoms found in people with coeliac disease.

The gut symptoms seen in coeliac disease may not always be present in people with the neurological symptoms.

How is coeliac disease diagnosed?

Your GP will ask about your symptoms. Don't feel embarrassed about questions on the frequency and colour of your bowel motions.

Your doctor may also want to know whether you have lost weight or whether you have symptoms of anaemia (tiredness, exhaustion, pallor). The doctor may:

• examine your abdomen
• look for a blistering rash on your skin
• check for mouth ulcers.

Blood tests are then usually requested.

• Your doctor will check for anaemia, testing the levels of iron, folic acid and calcium in your blood.
• Another blood test detects antibodies that are often found in coeliac disease. Several antibodies are linked to the condition, but the most specific is anti-endomysial antibody. If this is present in the blood, you are very likely to have coeliac disease.

An endoscopy with biopsy is needed to diagnose coeliac disease. Your doctor should arrange this test at the endoscopy unit at your local hospital.

Children can have endoscopy under general anaesthetis (sedation) and adults may have sedation or a local anaesthetic that numbs the throat with a spray.

It's important that you continue to have a normal diet that contains gluten before having the blood tests and endoscopy for coeliac disease.

The NICE guideline recommends that if the diet has been changed, foods that contain gluten should be eaten in at least one meal everyday for at least six weeks before testing.

Endoscopy and biopsy

• A thin flexible tube with a tiny camera and clipper at its end is put into your mouth.
• The camera is guided down the oesophagus (gullet) into the stomach and then the small bowel.
• The clipper can be used to remove a small piece of the bowel lining during the procedure. This is called a biopsy. You will not feel any discomfort.
• The whole procedure takes about 10 minutes.
• The biopsy specimen will be sent to the laboratory to examine the size and shape of the villi. This will confirm diagnosis.
• It is usual to repeat this test after several months on a gluten-free diet, to check that the lining has recovered.

What else could it be?

Diarrhoea and weight loss can be due to several other causes.

• A bowel infection caused by parasites called Giardia lamblia and Strongyloides. If your symptoms start after a tropical holiday, one of these infections may be to blame.
• Overgrowth of bacteria in the small intestine.
• Lactose (milk) intolerance.
• Whipple's disease (a rare disease in men that prevents nutrients and fat being absorbed).
• Intestinal lymphoma (a type of cancer).

What treatment is available?

It's not possible to prevent coeliac disease, but a gluten-free diet can reverse damage to the small intestine. This requires considerable support and information..

After diagnosis your GP should refer you for a consultation with a dietitian, who can give you diet sheets and advice.

It's important that you receive regular follow up from your healthcare team. The general recommendations are to have an annual review appointment.

Another important aspect of treatment is recommending supplements for Vitamins and minerals.

If nutrient levels are low, you may need iron tablets, folic acid supplements and calcium. All women should take a folic acid supplement of 400 micrograms a day for three months before conception and for the first three months of pregnancy. This is to protect against neural tube defects such as spina bifida.

If your folic acid levels are low before conception you may need to take a higher dose of five milligrams a day.

It's important to discuss supplements with your GP or local dietitian as they can help to access your individual needs.

Coeliac disease that does not respond to a gluten-free diet may need additional treatment.

In the vast majority of cases, failure of the gut to heal is due to continued gluten in the diet.

If you have been told that your gut has not healed it is important that you see a registered dietitian who can discuss your diet in more detail. Refractory coeliac disease is a term used to describe a condition that does not respond despite following a strict gluten-free diet.

Treatment may include the use of steroids and drugs that 'damp down' the immune system. This is rare.

The gluten-free diet can be nutritionally adequate and balanced. However, the gluten-free diet can be low in fibre and wholegrains, which can cause constipation in some people.

To counteract this, eat plenty of fruit and vegetables.

Tips to increase your fibre intake when following a strict gluten-free diet can be found on the Coeliac UK website. If constipation persists, speak to your local pharmacist, dietitian or GP for further advice.

What is a gluten-free diet?

Things to avoid

The gluten-free diet involves avoiding gluten, the protein found in wheat, rye and barley. Some people are also sensitive to oats.

Gluten is found in the following foods.

• Bread, pasta and breakfast cereals.
• Pizza bases.
• Biscuits, cakes and pastries.
• Some soy sauces, mustards and mayonnaises.
• Some tinned soups, sauces, ready meals and some processed foods.
• Some crisps and similar snacks.
• Chips should be avoided if cooked in the same oil as battered fish.
• Beer, lager, stouts and ales are made from grain containing gluten, but other alcoholic drinks such as wine, cider, sherry, spirits and liqueurs can be included in the gluten-free diet.

Most people with coeliac disease can include gluten-free oats in the diet.

Oats are often processed and milled in the same place as wheat. It is therefore important that those including oats in the diet choose gluten-free oats.

Some people can be sensitive to gluten-free oats. This is because oats contain a gluten-like protein called avenin.

If you are thinking about including pure, uncontaminated oats in your gluten-free diet, you should discuss this with your healthcare team (GP, registered dietitian, gastroenterologist) for specific guidance and on-going monitoring.

Current recommendations are that all oats and oat products should be avoided for the first 6 months after diagnosis of coeliac disease to enable you to understand how it feels to be without symptoms.

Prescription medications and medications with a product licence number on the packet are gluten-free.

If a medicine contains wheat starch, this will be indicated on the label and in the patient information leaflet. If concerned you should check with your doctor or pharmacist before taking them.

Foods you can eat

Many foods do not contain gluten, including:

• all fruit, salads, vegetables
• potatoes
• rice and maize
• nuts
• pulses and lentils
• red meat, chicken, fish, eggs and dairy products
• processed foods such as ready meals and soups which are made without gluten

Coeliac UK produce a food and drink directory, listing foods that can be included in the gluten-free diet.

Gluten-free substitutes are available from most supermarkets and pharmacies. You can also get staples such as gluten-free flour, breads and pasta on prescription from your doctor.

There are excellent books available on gluten-intolerance, including general guides and recipe books.

What complications can coeliac disease cause?

Complications of coeliac disease are rare. They include the following.

Term watch

Autoimmune disease: a disease where the immune system attacks the bodies own cells.

Coeliac disease is an autoimmune disease.

• Infertility in women. Recurrent miscarriage is sometimes associated with coeliac disease.
• Severe anaemia in pregnancy because the bowel cannot absorb enough iron and vitamins to keep up with the demands of mother and baby.
• Intrauterine growth retardation. Babies who are small for their age in the womb are more frequently born to mothers with coeliac disease.
• Autoimmune diseases (thyroid disease, Type 1 diabetes and some types of liver disease such as primary biliary cirrhosis).
• Thinning of the bones (osteoporosis).
• A slightly increased risk of developing bowel cancer, intestinal lymphoma and cancer of the oesophagus.

A gluten-free diet reduces all these complications, as well as treating associated symptoms and conditions such as diarrhoea, mouth ulcers and dermatitis herpetiformis.

Studies have shown that sticking to a gluten-free diet for five years or more reduces the risk of all cancers associated with coeliac disease to that of the general population.

Is there a cure for coeliac disease?

A gluten-free diet should enable the lining of the bowel to return to normal in most people. But damage will return as soon as you start eating gluten again.

This means the disease can be 'cured', but only by avoiding foods that contain gluten. If you do this, you can enjoy a good quality of life without symptoms or long-term complications.

Support groups

Coeliac Uk can offer support to help you manage your gluten-free diet. A Helpline is also available on 0845 305 2060 for any questions you have on coeliac disease diagnosis or treatment.

http://www.netdoctor.co.uk/diseases/facts/glutenallergy.htm