Coeliac disease is caused by an immune reaction to gluten, a protein found in wheat, barley and rye. The reaction causes inflammation and damage to the lining of the small bowel, which impairs its ability to absorb nutrients. Typical symptoms include mouth ulcers, fatigue, bloating, cramps and diarrhoea, but some people have no symptoms at all, and in others the only clue may be anaemia (due to iron or folic acid deficiency) or an unusual chronic skin rash (dermatitis herpetiformis). Coeliac disease should not be confused with wheat allergy, which rarely occurs beyond infancy, or the stomach and bowel irritation that gluten can sometimes cause in people with chemical intolerances.
Screening blood tests are available, but definite diagnosis requires a small bowel biopsy. These tests can become negative after a few weeks of gluten avoidance, so it’s best to get checked before you go on a gluten-free diet if you think there’s a possibility you might have coeliac disease.
Untreated coeliac disease carries a long-term risk of nutritional deficiency, osteoporosis and/or bowel malignancy. Currently, a life-long gluten-free diet is the only known treatment.