Definition and symptoms of Crohn disease in adults

Gastroenterological Society of Australia (GESA), 2018Lichtenstein, 2018

Crohn disease is a chronic, relapsing, immune-mediated inflammatory bowel disease, which can be associated with a range of extra-intestinal manifestations (eg arthropathy, skin manifestations [eg pyoderma gangrenosum, erythema nodosum], ocular manifestations [eg uveitis, scleritis, episcleritis], and hepatobiliary disease)Lichtenstein, 2018. Crohn disease is characterised by inflammation affecting all layers of the intestinal mucosa; it can occur in any part of the gastrointestinal tract and may be discontinuous. The symptoms associated with Crohn disease vary depending on the part of the gastrointestinal tract affected. Typical symptoms include abdominal pain, diarrhoea, unintentional weight loss, fatigue and unexplained anaemia.

Both genetic and environmental factors are important in the aetiology of Crohn disease. Genetic contributions to the development of Crohn disease are stronger than for ulcerative colitis; up to 30% of the risk may be attributed to genetic predisposition. Environmental factors include the ‘Western diet’ (ie a diet characterised by high-fat, high-sugar and highly processed foods) and smoking.

For information about inflammatory bowel disease in children, see Inflammatory bowel disease in children.