Crohn Disease
Also known as Crohns, Inflammatory bowel disease
This article is general health information for the selected condition. It is not a diagnosis and does not replace clinical judgement. If you have questions or need treatment advice, please consult a qualified healthcare professional.
What is crohn disease?
Crohn disease is a chronic inflammatory bowel disease that can affect any part of the digestive tract from mouth to anus, most commonly the end of the small intestine. Inflammation extends through the full thickness of the bowel wall, which is why complications such as strictures and fistulas occur. It follows a relapsing and remitting course.
Causes
- Dysregulated immune response to gut bacteria
- Genetic susceptibility including NOD2 variants
- Alterations in the gut microbiome
- Environmental triggers, with smoking a clear contributor
Symptoms
- Persistent diarrhoea
- Abdominal pain and cramping, often in the right lower abdomen
- Weight loss and reduced appetite
- Fatigue
- Blood or mucus in the stool
- Mouth ulcers
- Perianal pain, abscess or fistula
Risk factors
- Family history of inflammatory bowel disease
- Smoking, which worsens Crohn disease specifically
- Age between 15 and 35 at onset
- Previous gastrointestinal infection
- Western dietary and urban living patterns
Diagnosis
- Colonoscopy with biopsies showing patchy transmural inflammation
- Faecal calprotectin to distinguish inflammation from functional symptoms
- MRI or CT enterography for small bowel disease
- Blood tests including inflammatory markers, iron and B12
- Stool testing to exclude infection
Treatment
- Corticosteroids to induce remission during flares
- Immunomodulators such as azathioprine or methotrexate
- Biologic therapy including anti TNF agents
- Exclusive enteral nutrition, particularly in children
- Smoking cessation
- Surgery for strictures, fistulas or disease not responding to medicines
Self care
- Take maintenance medicines even when you feel completely well
- Stop smoking, which clearly worsens Crohn disease
- Keep a food and symptom diary rather than eliminating foods broadly
- Work with a dietitian to avoid nutritional deficiency
- Attend blood monitoring for immunosuppressive medicines
- Keep vaccinations up to date, avoiding live vaccines on immunosuppression
- Plan travel with a supply of medicines and a letter
When to see a doctor
Book an appointment if:
- Increasing diarrhoea, pain or blood in stool
- Weight loss or persistent fatigue
- New perianal pain, swelling or discharge
- Joint pain, eye redness or new skin lesions
- Symptoms returning after a period of remission
- Before pregnancy, to plan treatment
Some symptoms need emergency care rather than an appointment. See the warning signs listed above.
Prevention
- Crohn disease cannot currently be prevented
- Flares are reduced by consistent maintenance treatment
- Stopping smoking substantially reduces flares and surgery
- Avoid unnecessary anti inflammatory painkillers
- Attend regular monitoring to catch inflammation before symptoms
Outlook
Crohn disease is lifelong and relapsing, but outcomes have improved considerably with early effective treatment. Many people achieve long remissions and work and live normally. Around half will need surgery at some point, usually for strictures or fistulas, and surgery is not curative. Stopping smoking and staying on maintenance therapy are the two biggest modifiable factors.
Common questions
How does Crohn disease differ from ulcerative colitis?
Crohn disease can affect any part of the digestive tract in patches and involves the full bowel wall thickness. Ulcerative colitis is limited to the colon, is continuous from the rectum upward, and affects only the inner lining.
Does diet cause Crohn disease?
Diet does not cause it, but certain foods can worsen symptoms during a flare. Exclusive enteral nutrition is an effective treatment in some patients, particularly children, and dietitian input is valuable.
Why is smoking singled out?
Smoking clearly worsens Crohn disease, increasing flares, surgery rates and post surgical recurrence. Stopping smoking is one of the most effective things a patient can do for their long term outcome.
References
Important: Dard AI is not a medical device and does not diagnose, treat, or replace clinician judgement. This article is general information only. Always consult a qualified healthcare professional about diagnosis and treatment, and seek emergency care for severe or rapidly worsening symptoms.