Coeliac disease is a digestive disease that damages the small intestine and interferes with absorption of nutrients from food. People who have coeliac disease cannot tolerate a protein called gluten, which is found in wheat, rye, barley, etc. When they eat foods containing gluten, their immune system responds by damaging the small intestine. As the body's own immune system causes the damage, coeliac disease is considered an autoimmune disorder. However, it is also classified as a disease of malabsorption because nutrients are not absorbed.

The exact cause of coeliac disease is unknown. There is evidence that the disorder is inherited since it tends to run in families. The disorder may be caused by an abnormal immune response to proteins found in grains, particularly gluten and the related protein gliadin. The intestines contain projections, called villi that normally absorb nutrients. Coeliac disease causes these villi to become flattened and lose the ability to absorb nutrients. Sometimes the disease is triggered or becomes active for the first time after surgery, pregnancy, childbirth, viral infection, or severe emotional stress.

The symptoms vary from person to person and, therefore, can be quite confusing. Most people have the symptoms outlined below. Occasionally, however, people with this condition have no symptoms at all or have bulky stool, even constipation, without weight loss or change in appetite.

In infants and children:

• Abnormal stools
   
• Diarrhoea
   
• Slow growth
   
• Irritability
   
• Bloody or clay-coloured, foul-smelling stools
   
• Vomiting
   
• Weight loss
   
• Decreased appetite (anorexia)
   
• Muscles in arms and legs are thin and wasted
   
• Abdominal distention

In adults:
 

• Abnormal appearance of the teeth
   
• Abdominal distention
   
• Abdominal pain
   
• Bloating
   
• Bone pain
   
• Bone tenderness
   
• Breathlessness due to anaemia
   
• Depression
   
• Diarrhoea
   
• Fatigue
   
• Irritability
   
• Muscle cramps
   
• Tiredness
   
• Vomiting
   
• Weight loss

Additional symptoms that may be associated with this disease are nosebleed, overall swelling and floating stools.

Typically, most people with coeliac disease will have symptoms of malabsorption such as diarrhoea. However, some will have bone disease, anaemia, or other conditions without diarrhoea. Compression fractures of the back, or other signs of bone disease may be present.

Dental examination may show changes in the teeth. In fact, some cases of coeliac disease are suspected by a dentist because of the changes in the enamel of the teeth, which include symmetrical changes in the tooth colour and surface texture.

A blood test often indicates anaemia. Two relatively new blood tests have improved the ability to accurately diagnose this disorder. Both, the IgA antiendomysial antibody and the antigliadin antibodies are sensitive and specific for the diagnosis of coeliac disease.

An endoscopy and small bowel biopsy, particularly biopsy of the jejunum (the part of the small intestine most often affected), will show an abnormal intestinal lining. Serial biopsies may be performed before and after a gluten-free diet. Improvement of the findings of biopsy (or improvement of symptoms) after a gluten- and gliadin-free diet is considered highly indicative of coeliac disease.

A life-long gluten-free diet is recommended. This allows the intestinal villi to heal.

Gluten-free diet:

Foods that contain wheat, rye, oats, and barley must be eliminated from the diet. Hidden sources of gluten include grain derivatives such as malt, modified food starch, soy sauce (some types), grain vinegar, and some binders, fillers, and flavourings should be avoided. Despite these restrictions, people with coeliac disease can eat a well-balanced diet with a variety of foods, including bread and pasta. For example, instead of wheat flour, people can use potato, rice, soy, or bean flour. Or, they can buy gluten-free bread, pasta, and other products from special food companies. Plain meat, fish, rice, fruits, and vegetables do not contain gluten, so people with coeliac disease can eat as much of these foods as they like.

The gluten-free diet is complicated. It requires a completely new approach to eating that affects a person's entire life. Eating out can be a challenge as the person with coeliac disease learns to scrutinize the menu for foods with gluten and about possible hidden sources of gluten. Hidden sources of gluten include additives, preservatives, and stabilisers found in processed food, medicines, and mouthwash. A dietician, or a health care professional who specializes in food and nutrition, can help people learn about their new diet.

A small percentage of people with coeliac disease do not improve on the gluten-free diet. These people often have severely damaged intestines that cannot heal even after they eliminate gluten from their diet. Because their intestines are not absorbing enough nutrients, they may need to receive intravenous nutrition supplements. Drug treatments are being evaluated for unresponsive coeliac disease. These patients may need to be evaluated for complications of the disease.

Vitamin and mineral supplements may be needed to correct nutritional deficiencies. Sometimes, corticosteroids (such as prednisone) may also be required. The stress of a chronic disorder such as coeliac disease can sometimes be helped by joining a support group where members share common experiences and problems.

Untreated, the disorder can cause life-threatening complications. Symptoms usually disappear within several weeks after the person begins a gluten-free diet. The gluten-free diet must be followed continuously or the symptoms will return.