Ulcerative colitis

Ulcerative colitis — inflammation of the colon

Ulcerative colitis (UC) is a chronic inflammatory bowel disease causing inflammation and ulcers of the colon (large intestine) and rectum — and nowhere else in the gut. It affects roughly 1 in 420 people in the UK.

Inflammation starts at the rectum and extends continuously upward — unlike Crohn’s patchy involvement. Severity depends on how much colon is affected: proctitis (rectum only), left-sided, or extensive/pancolitis.

Symptoms

During active disease:

• bloody diarrhoea — hallmark feature
• mucus in stool
• urgency — sudden need to defecate, sometimes incontinence if severe
• tenesmus — feeling of incomplete emptying
• abdominal cramps — usually before bowel movements
• fatigue, weight loss, anaemia
• fever in moderate-to-severe flares

Between flares: may be completely well — remission is the treatment goal.

Acute severe ulcerative colitis — emergency

Truly urgent — hospital admission needed:

• 6 or more bloody stools daily
• plus heart rate over 90, temperature over 37.8°C, CRP elevated, or haemoglobin low

Without treatment: toxic megacolon (colon dilates — perforation risk), severe bleeding, sepsis.

Do not wait — same-day gastroenterology assessment.

Diagnosis

• blood tests — inflammation, anaemia
• stool tests — exclude infection (Campylobacter, Salmonella, C. difficile especially if recent antibiotics)
• faecal calprotectin — elevated in IBD
• colonoscopy with biopsies — confirms diagnosis, assesses extent

Treatment

Mild to moderate proctitis or left-sided

• Topical mesalazine suppositories or enemas — first-line for distal disease
• Oral aminosalicylates (mesalazine) — maintenance

Moderate flare

• Oral steroids (prednisolone) — induce remission — not for long-term maintenance due to side effects
• Oral + topical mesalazine

Moderate to severe or steroid-dependent

• Thiopurines (azathioprine)
• Biologics — infliximab, adalimumab, vedolizumab, tofacitinib (JAK inhibitor)
• Hospital IV steroids or ciclosporin for severe acute colitis

Maintenance

• Mesalazine long term — reduces flare risk and may lower cancer risk
• Regular monitoring — bloods every 3 to 6 months on immunosuppressants

Surgery

Subtotal colectomy when:

• medically refractory disease
• acute severe colitis failing IV treatment
• dysplasia or cancer
• complications ( perforation, megacolon)

Options: permanent ileostomy or ileo-anal pouch (J-pouch) — multi-stage surgery with gastroenterology and colorectal surgical team.

Cancer surveillance

Long-standing extensive colitis increases colon cancer risk — roughly 2% per decade after 10 years for pancolitis. Regular colonoscopy with biopsies (surveillance) detects precancerous changes.

Living with ulcerative colitis

• take maintenance medicines even when well — stopping invites flare
• know your flare early signs
• Iron replacement if anaemic
• Crohn’s and Colitis UK support
• travel planning — know toilet access; carry urgent card
• pregnancy — usually safe in remission — specialist preconception advice

Ulcerative colitis is serious but treatable — modern biologics mean many people achieve durable remission without surgery. Early recognition of severe flares saves lives.

Common questions

What are the first signs of ulcerative colitis?

Often gradual onset — increased bowel frequency, loose stools with blood or mucus, urgency (need to reach toilet quickly), cramping lower abdominal pain, and fatigue. Some present acutely with severe bloody diarrhoea. Onset is usually under 30 but can occur at any age.

Is ulcerative colitis the same as Crohn's disease?

Both are IBD but colitis affects only colon and rectum with continuous superficial inflammation; Crohn's can affect any gut segment with deeper patchy inflammation. Colitis causes bloody diarrhoea more consistently; Crohn's more often causes fistulas and small bowel problems.

Can ulcerative colitis be cured?

Medicines can induce long remission but there is no medical cure. Colectomy (surgical removal of colon) cures colitis — ileostomy or pouch reconstruction — but is reserved for medically refractory disease or complications. Most people manage with medicines long term.

What triggers ulcerative colitis flares?

Often no clear trigger. Stopping medicines is a common cause. Infections (including C. difficile), NSAIDs, smoking cessation (unlike Crohn's, smoking oddly protects colitis — still never start smoking), and stress may worsen flares. Diet does not cause colitis but some foods aggravate symptoms individually.

How often do I need colonoscopy with ulcerative colitis?

Surveillance starts 8 to 10 years after diagnosis for extensive colitis — typically every 1 to 5 years depending on disease duration and extent — to detect dysplasia and cancer early. Your gastroenterologist schedules this.

Sources

• NHS — Ulcerative colitis
• NICE — Ulcerative colitis management