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Crohn's disease

An ESCP Guide for Patients

View our short printable guide

What is Crohn’s disease?

Crohn’s disease is a long-term condition where parts of your digestive system become inflamed. It is one of the two main types of inflammatory bowel disease (IBD) - the other is ulcerative colitis (UC). The inflammation is chronic and caused by an autoimmune response, meaning the immune system mistakenly attacks the body’s own tissues.

Crohn’s can affect any part of your digestive tract - from the mouth to the anus - but it most often affects the end of the small intestine and the beginning of the large intestine (colon).

Key features

  • Lifelong condition: chronic and relapsing in nature; you may have periods when symptoms are mild or gone (remission) and times when they flare up
  • Deep inflammation: it can affect the entire thickness of the bowel wall, not just the surface
  • Patchy involvement: healthy parts of the bowel can be found between inflamed areas (known as 'skip lesions')
  • May affect the anal area: patients often develop cracks, tunnels (fistulas), or abscesses near the anus

Illustration showing a normal colon and one with Crohn's disease, showing thickening of colon wall, cobblestone appearance of surface, and a fistula

Causes and risk factors of Crohn’s disease

The exact cause is unknown, but several factors may play a role:

  • Immune system problems: your immune system may overreact to bacteria in your gut
  • Family history: Crohn’s is more likely if a close relative has IBD
  • Smoking: increases the risk and can worsen the disease
  • Diet and environment: may influence onset or symptoms but do not directly cause Crohn’s
  • Gut bacteria: an imbalance in gut bacteria might trigger inflammation

Graphic showing risk factors for Crohn's disease as described above

Symptoms of Crohn’s disease

Symptoms can vary, depending on which part of the gut is affected and the severity:

  • Stomach pain or cramping (often in the lower right side)
  • Persisting diarrhoea, sometimes with blood
  • Fatigue and tiredness
  • Weight loss
  • Fever
  • Poor appetite
  • Mouth ulcers
  • Malnutrition and deficiencies (due to impaired nutrient absorption)
  • Sores, abcesses or pain near the anus (perianal disease)
  • Problems outside the gut, such as:
    • Joint pain (arthritis)
    • Skin rashes
    • Eye inflammation

Possible complications

Crohn’s can sometimes lead to serious problems when symptoms or the disease worsen.

  • Narrowed or blocked intestines (strictures)
  • Tunnels (fistulas) or infected areas (abscesses)
  • Poor nutrient absorption, causing deficiencies
  • Higher risk of colon cancer with persisting inflammation

How is Crohn’s disease diagnosed?

A combination of tests is used to diagnose Crohn’s disease:

  • Colonoscopy or endoscopy: a camera is used to look inside your gut and take tissue samples
  • MRI or CT scan: to see detailed images of your intestines
  • Blood tests: to check for inflammation, anemia, or infection
  • Stool tests: to rule out infections and check inflammation levels (e.g. calprotectin)

Timely and accurate diagnosis is essential to quickly start effective treatment.

Treatment options for Crohn’s disease

There is no cure yet, but many treatments can control symptoms and maintain remission to help you live a full life.

Diet and lifestyle

  • Eat a healthy, balanced diet
  • Avoid trigger foods - may vary from person to person
  • Follow a low-fibre diet during flare-ups
  • Stop smoking - it makes Crohn’s worse
  • Take supplements for any deficiencies

Medications

The main goal of medical treatment for Crohn’s disease is to reduce the inflammation in your gut, relieve your symptoms, and prevent flare-ups. This helps your bowels heal. Reducing inflammation is done via different pathways:

  • Anti-inflammatory drugs: corticosteroids and 5-ASA compounds
  • Immune modulators (immunosuppressors): azathioprine, methotrexate
  • Biologic therapies: anti-TNF agents (e.g. infliximab, adalimumab), inhibitors of interleukins/janus kinases
  • Antibiotics: for infections or abscesses

Surgery

If medicine does not control your symptoms or if complications occur, surgery may be needed. Reasons for surgery:

  • Narrowing (strictures) blocking the bowel
  • Fistulas or abscesses that don't heal or require drainage
  • Severely damaged bowel that needs to be removed
  • Bowel resection removing the affected part of the gut
    • In severe cases, removing the affected part of the intestine can manage symptoms and prevent complications. For example, an ileocecal resection (removal of the last part of the small intestine and a portion of the colon) may be recommended for localised Crohn’s disease, potentially reducing the need for medication afterward.
  • Stoma creation: creating an opening (ileostomy or colostomy) for waste to leave the body is sometimes necessary to alleviate inflammation further down the bowel

Surgery is often helpful, but Crohn’s disease can still return in other parts of the bowel.

Making treatment decisions

All treatment plans are made together with your healthcare team. This includes your gastroenterologist, surgeon, dietitian, and most importantly - you.

They will help choose the best approach for your individual needs, lifestyle, and preferences.

Living with Crohn’s disease

With the right treatment, many people live active, full lives.

  • Stay in touch with your medical team and attend regular check-ups
  • Learn what triggers your symptoms and try to avoid them.
  • Support groups and Crohn’s/IBD communities can be very helpful

If you have any concerns or need further information, please speak to your healthcare provider.

Patient information websites

Disclaimer

The information provided here is general and hopes to correctly inform the patient to the extent possible. However, this document cannot discuss all aspects of a specific condition or procedure, or of the individual patient.

The decision on which procedure will give you the best result is made by your doctor or colorectal surgeon during consultation and based on shared and informed decision-making with the patient.