Ulcerative colitis
A long-term inflammatory bowel disease in which the lining of the large intestine (colon) and rectum becomes inflamed and ulcerated. It causes bouts of bloody diarrhoea, urgency and abdominal pain, running a relapsing-remitting course, and is treated to control inflammation and keep it in remission.
What it is
Ulcerative colitis is one of the two main forms of inflammatory bowel disease (the other being Crohn's disease). It is a chronic, immune-driven condition in which the inner lining of the large bowel — the colon and rectum — becomes inflamed, ulcerated and prone to bleeding. Unlike Crohn's, it involves only the large bowel and only its surface lining, and it typically starts in the rectum and extends a continuous distance up the colon. The cause is not fully understood but involves the immune system reacting abnormally, on a background of genetic susceptibility and gut-environment factors. It usually begins in early adulthood and follows a relapsing-remitting course: flares of active inflammation alternating with periods of remission. During a flare the classic symptoms are diarrhoea often mixed with blood and mucus, an urgent need to pass stool, abdominal cramps, and sometimes fever, tiredness and weight loss; long-standing or severe disease can cause anaemia and low albumin. Some people also get inflammation outside the gut, in the joints, skin or eyes. A severe flare can be dangerous. Diagnosis is confirmed by colonoscopy with biopsies, supported by blood tests and faecal calprotectin. Treatment aims to bring flares under control and maintain remission with anti-inflammatory and immune-modifying medicines; long-standing colitis also raises the risk of bowel cancer, so surveillance colonoscopy is offered.
Key lab markers
- Faecal calprotectin — a stool marker of bowel inflammation; raised in active disease and used to monitor activity and flares.
- CRP (and ESR) — inflammation markers, often raised in a flare.
- Haemoglobin — may be low (anaemia) from chronic blood loss and inflammation.
- Albumin — can fall in active, severe disease.
- Note — the diagnosis is confirmed by colonoscopy and biopsy, not by blood tests alone.
Symptoms
- Diarrhoea, often with blood and mucus
- An urgent need to open the bowels, and a feeling of incomplete emptying
- Abdominal cramps and pain
- Tiredness and, in a flare, fever
- Weight loss and reduced appetite
- Pallor and fatigue if anaemia develops
- Sometimes joint pain, skin rashes or eye inflammation
Related symptoms
Related lab panels
When to discuss with a doctor
See a doctor for persistent diarrhoea, especially if there is blood or mucus in the stool, an urgent need to open the bowels, or ongoing abdominal pain — these need investigation, usually including faecal calprotectin, blood tests and a colonoscopy. In someone already diagnosed, a flare that is not settling, worsening bleeding, high fever, severe abdominal pain, or feeling very unwell needs prompt medical attention, as a severe flare can be serious. Taking maintenance treatment as prescribed helps keep the disease in remission, and attending surveillance colonoscopy matters because long-standing colitis raises bowel-cancer risk. Mediora.AI can surface the pattern of a raised faecal calprotectin and CRP with a low haemoglobin and albumin that points to active bowel inflammation, but the diagnosis, monitoring and treatment belong with your doctor and gastroenterology team.