What is ulcerative colitis?
Ulcerative colitis is an inflammatory bowel disease in which the immune system inflames and ulcerates the lining of the large bowel, always involving the rectum and extending a variable distance around the colon. It flares and remits: during flares people experience bloody diarrhoea, urgency and cramping, while remission can last months or years, particularly with modern maintenance treatment.
Colitis most commonly begins between the ages of 15 and 35, with a second smaller peak in later life, and affects men and women equally. Diagnosis is made by colonoscopy or flexible sigmoidoscopy with biopsies, supported by blood tests and the stool inflammation marker faecal calprotectin, which distinguishes colitis from IBS. Because long-standing colitis modestly raises bowel cancer risk, surveillance colonoscopies are offered after eight to ten years.
Common symptoms
- Diarrhoea, often with blood or mucus
- Urgent, sometimes uncontrollable need to open the bowels
- Cramping abdominal pain, often left-sided
- Fatigue
- Weight loss during flares
- Feeling of incomplete emptying (tenesmus)
- Joint pains, eye or skin inflammation in some people
How long will you wait?
Routine NHS referrals for suspected colitis commonly wait two to four months for clinic and endoscopy, though patients with significant bleeding or severe symptoms are triaged to be seen much sooner.
Privately, you can typically see a consultant within 3–7 days, with colonoscopy usually within 1–2 weeks and treatment started immediately after diagnosis.
NHS England median referral-to-treatment wait: 12.4 weeks, with 2.5 million people waiting over 18 weeks (May 2026). Individual waits vary by trust and urgency.
Treatment options
- 5-ASA drugs (mesalazine). Anti-inflammatory tablets, enemas or suppositories that both treat mild flares and maintain remission.
- Corticosteroids. Short courses settle moderate to severe flares but are unsuitable for long-term use.
- Biologics and small molecules. Drugs such as infliximab, vedolizumab and JAK inhibitors control disease that does not respond to first-line treatment.
- Colectomy. Surgical removal of the colon cures the bowel disease itself and is used for emergencies or medically resistant colitis, often with a pouch or stoma.
What does private treatment cost?
As a guide, a private colonoscopy with biopsies typically costs around £1,800–£2,800 in the UK in 2026, with initial consultation and stool and blood testing typically adding around £300–£500.
Does health insurance cover ulcerative colitis?
Private medical insurance typically covers the investigations that lead to a colitis diagnosis and treatment of acute flare-ups, and surgery such as colectomy is usually covered where clinically required. As with Crohn's disease, though, ulcerative colitis is classed as chronic: maintenance drugs, surveillance colonoscopies and routine specialist follow-up are generally not covered long term and are handled by the NHS. A diagnosis made before your policy began will normally be excluded.
Frequently asked questions
How is ulcerative colitis different from Crohn's disease?
Both are inflammatory bowel diseases, but colitis affects only the large bowel and inflames just its inner lining in a continuous stretch starting at the rectum. Crohn's can strike anywhere from mouth to anus, in patches, and burrows deeper through the bowel wall, which is why fistulas and strictures are more of a Crohn's problem. Treatment overlaps considerably, but surgical options differ importantly.
Does ulcerative colitis increase my risk of bowel cancer?
Long-standing, extensive colitis does raise the risk above the general population's, which is why guidelines recommend surveillance colonoscopies starting around eight to ten years after diagnosis, at intervals tailored to your individual risk. Two reassurances: the absolute risk for most people remains modest, and keeping inflammation well controlled with maintenance treatment appears to reduce it. Attending surveillance reliably is one of the most protective things you can do.
Can surgery really cure colitis?
Because colitis is confined to the colon and rectum, removing them removes the disease, something not true of Crohn's. After colectomy, people either have an ileostomy (stoma bag) or a pouch constructed from small bowel that restores near-normal toilet function. Neither is undertaken lightly, but for people with severe or uncontrollable disease, surgery frequently transforms quality of life rather than diminishing it.
Related guides
- Acid Reflux (GORD)
- Barrett's Oesophagus
- Coeliac Disease
- Crohn's Disease
- Diverticular Disease
- Irritable Bowel Syndrome (IBS)