coeliac

Coeliac disease, commonly spelled coeliac in British English and celiac in American English, is a chronic autoimmune enteropathy triggered by gluten-containing foods in genetically susceptible individuals. Gluten is found in wheat, barley, and rye. The disease causes inflammation and damage to the lining of the small intestine, which can impair nutrient absorption.

Pathophysiology involves an autoimmune reaction to gluten proteins, particularly gliadin, with involvement of tissue transglutaminase 2 (TTG2). This leads to villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis in the small intestine. Most patients carry the HLA-DQ2 or HLA-DQ8 gene, though these genes are not diagnostic on their own.

Symptoms vary widely. Classical presentations include chronic diarrhea, abdominal pain, bloating, and weight loss, especially in children. Many patients have non-gastrointestinal manifestations such as iron-deficiency anemia, fatigue, short stature, osteoporosis, infertility, and dermatitis herpetiformis. Onset can occur at any age, and some people are asymptomatic aside from laboratory abnormalities.

Diagnosis typically begins with serology, using IgA anti-tissue transglutaminase (TTG) antibodies and sometimes anti-endomysial antibodies, along with measurement of total IgA. If IgA deficiency is present, IgG-based tests are used. A small bowel biopsy showing villous atrophy confirms the diagnosis in most cases, with genetic testing for HLA-DQ2 or DQ8 supporting but not proving the diagnosis. Patients should be tested while still consuming gluten.

Treatment is lifelong adherence to a strict gluten-free diet, avoiding wheat, barley, and rye. Nutritional supplementation may be necessary, and most individuals improve clinically and histologically with treatment, though risks of osteoporosis, fertility issues, and certain cancers persist if the condition is not well controlled.