GPAtlas🧭 When to suspect
Crohn's disease is a chronic, relapsing–remitting transmural inflammation that can affect any part of the gut from mouth to anus, classically in discontinuous “skip lesions”, with the terminal ileum and ileocaecal region most commonly involved. Onset is usually before the age of 30 but it can present at any age.
Suspect Crohn's in a patient with persistent diarrhoea (typically > 4–6 weeks, which may be bloody or nocturnal), cramping abdominal pain (often right iliac fossa) and unexplained weight loss. Raise suspicion further when these are joined by systemic features (fatigue, fever, malaise) or by extra-intestinal manifestations – perianal disease, aphthous mouth ulcers, joint, eye or skin problems. Symptoms characteristically fluctuate between flares and remission. The primary-care skill is to recognise the pattern, use faecal calprotectin to separate inflammatory bowel disease from IBS, exclude mimics, and refer for colonoscopy and biopsy – the definitive diagnostic step.
| Feature | Crohn's disease | Ulcerative colitis |
|---|---|---|
| Distribution | Any site, mouth to anus; skip lesions (terminal ileum/ileocaecal common) | Colon only; continuous from the rectum |
| Depth | Transmural (full thickness) | Mucosal / submucosal |
| Characteristic features | Perianal disease, fistulae, strictures, abscesses | Bloody diarrhoea, urgency, tenesmus |
| Smoking | Worsens disease and post-operative recurrence | Associated with reduced risk (“protective”) |
| Histology | Non-caseating granulomas (not always seen) | Crypt abscesses, goblet-cell depletion |
Source: British Society of Gastroenterology · NICE NG129
🔒 Sign up free to read the full topic
You're viewing a free preview. Create a free account to unlock the rest.
Sign up free →Sample topics are open to everyone in the Free Sample Bundle.