Written by A/Prof Viraj Kariyawasam, Gastroenterologist

1. What is Crohn’s Disease?

Crohn’s disease is a chronic inflammatory bowel disease (IBD) that causes ongoing inflammation of the digestive tract. It can affect any part of the gastrointestinal system from the mouth to the anus, but most commonly involves the end of the small bowel (ileum) and the beginning of the large bowel. Crohn’s disease affects people of all ages and often begins in adolescence or early adulthood.

2. Causes & Risk Factors

The exact cause of Crohn’s disease is not known. It is thought to occur when the immune system reacts abnormally to normal gut bacteria in people who are genetically susceptible.

Risk factors include having a close family member with Crohn’s disease or ulcerative colitis, smoking (which significantly worsens disease outcomes), and living in industrialised countries such as Australia. Certain medications, including non-steroidal anti-inflammatory drugs, may trigger flares.

3. Symptoms & How It May Present

Symptoms vary depending on which part of the bowel is affected and the severity of inflammation. Common symptoms include abdominal pain, chronic diarrhoea, fatigue, weight loss, and reduced appetite.

Some people experience rectal bleeding, fever, nausea, vomiting, or pain around the anus due to fistulas or abscesses. Crohn’s disease can also affect other parts of the body, causing joint pain, skin rashes, eye inflammation, or mouth ulcers.

4. How Is It Diagnosed?

Diagnosis involves a combination of clinical assessment and investigations. Blood tests may show inflammation, anaemia, or nutritional deficiencies. Stool tests are used to assess inflammation and exclude infection.

Colonoscopy allows direct examination of the bowel and biopsy sampling. Imaging tests such as MRI, CT scans, or intestinal ultrasound are often used to assess the small bowel and detect complications such as strictures or fistulas.

5. Treatment & Management Options

There is currently no cure for Crohn’s disease, but effective treatments can control inflammation, relieve symptoms, and reduce complications. Treatment is individualised based on disease severity and location.

Medications may include corticosteroids for short-term control of flares, immune-modifying drugs, and biologic or targeted therapies. Some patients benefit from nutritional therapies. Surgery may be required if complications develop, but it does not cure the disease.

6. Living With / Managing Crohn’s Disease

Crohn’s disease typically follows a relapsing and remitting course. Long-term management focuses on maintaining remission and preventing complications.

Taking medications as prescribed, avoiding smoking, maintaining good nutrition, and attending regular follow-up appointments are essential. Support from dietitians, IBD nurses, and psychological services can significantly improve quality of life.

7. Prevention & Risk Reduction

There is no proven way to prevent Crohn’s disease. However, stopping smoking is the single most important modifiable factor to reduce disease severity and complications.

Early diagnosis, appropriate treatment, and regular monitoring help reduce hospitalisation, surgery, and long-term bowel damage.

8. When to Seek Medical Advice

You should seek medical attention if you experience persistent diarrhoea, abdominal pain, blood in the stool, unexplained weight loss, fever, or symptoms that are worsening despite treatment.

Urgent review is required for severe pain, vomiting, bowel obstruction symptoms, high fever, or significant bleeding.