Overview
Ulcerative colitis is a chronic inflammatory bowel disease that causes inflammation and ulcers in the lining of the large bowel (colon and rectum). Unlike Crohn's, it affects a continuous area and only the inner lining of the bowel. It runs a relapsing and remitting course, with flares of bloody diarrhoea followed by periods of remission. Long-standing extensive disease can increase the risk of bowel cancer, so ongoing monitoring is important.
Symptoms
- Diarrhoea, often with blood or mucus
- Urgent or frequent need to pass stool
- Abdominal cramping, often on the left side
- A feeling of needing to empty the bowel even when it is empty
- Fatigue
- Weight loss during flares
- Fever during severe flares
Causes & risk factors
- An abnormal immune response targeting the bowel lining
- Genetic and family-history factors
- Altered gut bacteria
- Environmental triggers
- Flares sometimes linked to infections or stress (which do not cause the disease itself)
Treatment & self-care
Care focuses on calming flares, keeping the disease in remission, and surveillance for complications. This usually involves specialist-prescribed anti-inflammatory or immune-modifying treatments tailored to disease extent and severity, regular monitoring, and colonoscopy surveillance over time. Surgery to remove the colon may be considered in severe or unresponsive disease. Treatment is lifelong and must be guided by a gastroenterologist.
See a doctor urgently if
- You have ongoing bloody diarrhoea
- You have unexplained weight loss or persistent fatigue
- You have frequent urgent bowel movements disrupting daily life
- Seek emergency care for a severe flare with frequent bloody stools, high fever, rapid heartbeat, and a painful swollen abdomen (possible toxic megacolon)
This condition can be an emergency. If any of the signs above are severe or getting worse, go to the nearest emergency room now or call your local emergency number — do not wait for an online consultation.