What causes Crohn's disease?

In Crohn's disease, the immune system reacts in an ongoing or poorly controlled way within the digestive tract. A person's inherited biology can influence this response, while the gut microbiome and environmental exposures may also shape it. These factors interact rather than acting as a single trigger.

Food choices do not create Crohn's disease, and the condition is not contagious. Smoking can worsen Crohn's disease and is worth discussing with a clinician. Stress may aggravate symptoms for some people, but it is not a simple explanation for the underlying disease.

You do not need to identify one cause before seeking care. Record changes in bowel habit, abdominal pain, weight, appetite, and possible triggers, then share the pattern at a GP consultation. A clinician may use your history, examination, and a blood test alongside other assessments to understand inflammation and possible consequences.

Take prescribed treatment as directed and discuss smoking, medicines, diet, and family history openly. Avoid restrictive diets or stopping treatment without professional advice, because removing foods without a plan can worsen nutritional intake.

Arrange an assessment for ongoing diarrhoea, repeated abdominal pain, blood in the stool, unexplained weight loss, fever, or marked tiredness. Seek urgent help for severe pain, persistent vomiting, faintness, heavy bleeding, or inability to keep fluids down.

Which findings support Crohn's disease in my case? Could any medicine or infection be contributing to my symptoms? Would a blood test or specialist assessment help? What changes should prompt urgent review?