Ulcerative Colitis

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PatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.

See also: Ulcerative Colitis written for patients

Ulcerative colitis (UC) is an idiopathic chronic inflammatory disease of the colon that follows a course of relapse and remission. In a small number of cases, ulcerative colitis is associated with extra-intestinal features. Disease extent can be divided into:

  • Distal disease (left-sided colitis): colitis confined to the rectum (proctitis) or rectum and sigmoid colon (proctosigmoiditis).
  • More extensive disease includes: left-sided colitis (up to the splenic flexure, 40% of patients), extensive colitis (up to the hepatic flexure) and pancolitis (affecting the whole colon, 20% of patients).
  • Some patients with pancolitis may have involvement of the terminal ileum due to an incompetent ileocaecal valve.

It is sometimes difficult to distinguish between ulcerative colitis and isolated colonic Crohn's disease. These patients can be described as having indeterminate colitis.

  • Ulcerative colitis is the most common type of inflammatory disease of the bowel. It has an incidence in the UK of approximately 10 per 100,000 people annually and a prevalence of approximately 240 per 100,000.
  • Ulcerative colitis can develop at any age but peak incidence is between the ages of 15 and 25 years, with a second, smaller peak between 55 and 65 years.
  • Ulcerative colitis occurs in men and women at approximately equal rates.
  • The aetiology is unknown. Ulcerative colitis is probably an autoimmune condition triggered by colonic bacteria causing inflammation in the gastrointestinal tract.
  • A family history is present in around 25-40% of children; siblings of an individual with Crohn's disease are 17-35 times more likely than the general population to develop the condition.
  • There is concern that non-steroidal anti-inflammatory drugs (NSAIDs) may increase the risk of relapse or exacerbation of inflammatory bowel disease (IBD) - ulcerative colitis and Crohn's disease - but the evidence is not strong.
  • The risk of IBD is increased in women using oral contraceptives but the absolute increase in risk is very low.
  • The risk of ulcerative colitis is decreased in smokers.


  • The cardinal symptom is bloody diarrhoea.
  • Associated symptoms include colicky abdominal pain, urgency, or tenesmus (a feeling of incomplete defecation with an inability or difficulty to empty the bowel at defecation).
  • Disease limited to the rectum (proctitis) may present with constipation and rectal bleeding.
  • There may be symptoms of systemic upset, including malaise, fever, weight loss and symptoms of extra-intestinal (joint, cutaneous and eye) manifestations.
  • The presentation may mimic gastrointestinal infection and the history should include recent foreign travel in considering the possibility of an infective cause.
  • Recent medication history is also important in considering other possible causes of the presenting gastrointestinal upset.


  • Depending on disease severity, the patient may be clearly unwell, pale, febrile and dehydrated. He or she may have a tachycardia and hypotension.
  • Abdominal examination may reveal tenderness, distension or palpable masses.
  • If abdominal tenderness is associated with abdominal distension then acute admission to hospital is required, as the patient could have toxic megacolon, which is potentially fatal. Other warning signs of potentially severe disease include tachycardia, fever and anaemia.

Approximately 4% of patients will have extra-intestinal disease which may include:

  • Related to the activity of colitis:
    • Erythema nodosum.
    • Aphthous ulcers.
    • Episcleritis.
    • Acute arthropathy affecting the large joints (eg, the wrists, the hips and the knees).
  • Usually related to activity of colitis:
    • Pyoderma gangrenosum.
    • Anterior uveitis.
  • Not related to activity of colitis:
    • Sacroiliitis.
    • Ankylosing spondylitis.
    • Primary sclerosing cholangitis.

The diagnosis should be made on the basis of clinical suspicion supported by appropriate macroscopic findings on sigmoidoscopy or colonoscopy, typical histological findings on biopsy and negative stool examinations for infectious agents.

Up to 70% of children and teenagers referred to a paediatric gastroenterology centre with suspected IBD do not have the disease. Using a simple clinical case definition for suspected IBD in combination with a positive faecal calprotectin result increases the specificity to detect IBD and reduces the need for referral to a paediatric gastroenterology centre, with a very low risk of missing cases.[4] 

  • Initial investigations should include FBC, renal function and electrolytes, LFTs, ESR, CRP, iron studies, vitamin B12 and folate.
  • Faecal calprotectin is accurate in detecting colonic inflammation and can help identify functional diarrhoea.
  • Microbiological testing for Clostridium difficile toxin and other pathogenic organisms. C. difficile infection has a higher prevalence in patients with IBD, may not be confined to the colon and is associated with increased mortality. A minimum of four stool samples is required to detect 90% of cases.
  • Cytomegalovirus (CMV) should be considered in severe or refractory colitis, as reactivation is common in patients with IBD on immunosuppression.
  • Sigmoidoscopy and rectal biopsy: for all patients presenting with diarrhoea, rigid sigmoidoscopy should be performed unless there are immediate plans to perform flexible sigmoidoscopy.
  • Imaging:
    • Abdominal radiography is essential in the initial assessment of patients with severe colitis, in order to exclude colonic dilatation; it may also help assess disease extent in ulcerative colitis or identify proximal constipation.
    • Other imaging studies that may be used for the initial evaluation of a patient with IBD include abdominal ultrasound, CT, MRI, barium fluoroscopy and isotope-labelled scans.
  • Endoscopy:
    • Colonoscopy with multiple biopsies (at least two biopsies from five sites, including the distal ileum and rectum) is the first-line procedure for diagnosing colitis.
    • Full colonoscopy is rarely needed in acute severe colitis and may be contra-indicated. Upper gastrointestinal endoscopy should be considered if there is co-existing dyspepsia.
  • Initial investigations include:
    • FBC, renal function and electrolytes, LFTs, ESR and CRP.
    • Low magnesium and serum albumin levels are sometimes found in ulcerative colitis.
    • Stool culture, including ova, cysts and parasites and also C. difficile toxin.
    • Serological markers have been developed to differentiate ulcerative colitis from Crohn's disease. p-ANCA is more commonly associated with ulcerative colitis, whilst ASCA is more commonly associated with Crohn's disease.
  • Abdominal imaging: this is essential in the initial assessment of patients with suspected ulcerative colitis, to exclude toxic dilatation and perforation. It may also help to assess disease extent or identify proximal constipation. In milder forms, ultrasound, CT, MRI and radionuclide scanning may all be contributory.
  • Sigmoidoscopy and rectal biopsy: for all patients presenting with diarrhoea, rigid sigmoidoscopy should be performed unless there are immediate plans to perform flexible sigmoidoscopy.
  • Colonoscopy:
    • This is usually preferable to flexible sigmoidoscopy because the extent of disease can be assessed; however, in moderate-to-severe disease, there is a higher risk of bowel perforation and flexible sigmoidoscopy is safer.
    • The extent of the disease is defined as the proximal margin of macroscopic inflammation because this is most clearly related to the risk of complications, including dilatation and cancer.
    • It is advisable that patients with ulcerative colitis should have a colonoscopy after 8-10 years to re-evaluate disease extent.

The National Institute for Health and Care Excellence (NICE) uses the categories of disease severity of mild, moderate and severe, based on the Truelove and Witts' severity index for adults and the Paediatric Ulcerative Colitis Activity Index (PUCAI) for children and young people.

For adults:

  • Mild: fewer than four stools daily, no more than small amounts of blood in stools, no anaemia, pulse rate not above 90, no fever and normal ESR and CRP.
  • Moderate: four to six stools a day with more blood in stools than for mild disease. No anaemia, pulse rate not above 90, no fever and normal ESR and CRP.
  • Severe: six or more stools per day, visible blood in stools and at least one feature of systemic upset (temperature above 37.8°C, pulse rate greater than 90, anaemia, ESR above 30).

PUCAI for children and young people includes scoring of the presence and severity of abdominal pain, rectal bleeding, stool consistency of most stools, number of stools per 24 hours, stools causing wakening at night and level of activity. Details can be found in the NICE guideline.

Subacute ulcerative colitis is defined as moderately to severely active ulcerative colitis that would normally be managed in an outpatient setting and does not require hospitalisation or the consideration of urgent surgical intervention.

  • Patients with severe colitis should be admitted to hospital for assessment and treatment.
  • Patients with moderate disease, who fail to respond to steroids within two weeks, should be admitted to hospital.
  • Patients who respond partially to treatment should be seen urgently in the outpatient department and treated for refractory colitis.
  • Topical management is appropriate for some patients with active disease. This is usually the case for those with proctitis and often the case if the disease extends into the sigmoid.
  • For those with more extensive disease, oral or parenteral therapy is the mainstay  of treatment, although some of these patients may get additional benefit from topical therapy.
  • Leukophoresis (extracorporeal removal of leukocytes from the blood) may be beneficial in carefully selected patients with ulcerative colitis. It is available in specialised centres as part of research trials.[7][8] A recent meta-analysis found that leukophoresis was more efficacious than conventional pharmacotherapy in improving response and remission rate.[9]
  • Beware antimotility drugs (eg, codeine, loperamide) and antispasmodic drugs, which may precipitate paralytic ileus and megacolon in active ulcerative colitis.

Drug treatments


  • Mesalazine - 5-aminosalicylic acid (5-ASA) - is now the treatment of choice for induction and maintenance of remission of mild-to-moderate ulcerative colitis.[10] Oral mesalazine is less effective than oral corticosteroids and so should be used as sole treatment only in mild attacks. Topical mesalazine is probably slightly more effective than topical corticosteroids.
  • Oral mesalazine is mostly used to maintain remission. Mesalazine also seems to help reduce the risk of colorectal cancer.
  • Modified once-daily mesalazine preparations and a multi-matrix oral formulation are now available for patients who have compliance problems.[11][12]
  • The newer 5-ASA preparations olsalazine and balsalazide are inferior to sulfasalazine in maintenance therapy but have fewer adverse effects. Sulfasalazine has a higher incidence of side-effects compared with newer 5-ASA drugs but selected patients (eg, those with a reactive arthropathy) may benefit.
  • Olsalazine has a higher incidence of diarrhoea in pancolitis and is best for patients with left-sided disease, or intolerance of other 5-ASAs.


  • Corticosteroids are used to induce remission in relapses of ulcerative colitis. They have no role in maintenance therapy.
  • Corticosteroids may be applied topically (suppositories, liquid or foam enemas), orally or intravenously (IV).


  • Azathioprine and its active metabolite 6-mercaptopurine may be used when:
    • Patients are intolerant to corticosteroids.
    • Patients need two or more corticosteroid courses in a calendar year.
    • Disease relapses when the dose of prednisolone is less than 15 mg a day.
    • Disease relapses within six weeks of stopping steroids.
  • Azathioprine seems to be effective for at least five years and increasing the duration of treatment will keep patients in remission for longer.


  • This is an effective salvage therapy for patients with severe refractory colitis and it has a rapid onset of action.
  • It reduces the colectomy rate by 50% in the short term but its use is controversial because of toxicity (drug-associated mortality is about 3%) and the long-term failure rate.


  • Infliximab is effective in inducing clinical remission in patients with moderate-to-severe ulcerative colitis, whose disease is refractory to conventional treatment using corticosteroids and/or immunosuppressive agents.[13]
  • Infliximab is recommended as an option for the treatment of acute exacerbations of severely active ulcerative colitis only in patients in whom ciclosporin is contra-indicated or clinically inappropriate.[14]
  • Infliximab is not recommended for the treatment of subacute manifestations of moderately to severely active ulcerative colitis.[14] 

Stool bulking agents

  • In left-sided disease, distal transit is rapid but proximal transit is slowed, which can result in proximal constipation.
  • Relief of proximal constipation by stool bulking agents or laxatives may help to induce remission in proctitis.

NICE guidance[1] 

Inducing remission in patients with mild-to-moderate ulcerative colitis

  • First presentation or inflammatory exacerbation of proctitis or proctosigmoiditis:
    • Topical aminosalicylate1 alone (suppository or enema); or
    • Consider adding an oral aminosalicylate to a topical aminosalicylate; or
    • Oral aminosalicylate alone (not as effective as a topical aminosalicylate alone or combined treatment).
    • If a patient cannot tolerate or declines aminosalicylates, or aminosalicylates are contra-indicated, offer a topical corticosteroid or consider oral prednisolone.
    • To induce remission in people with subacute proctitis or proctosigmoiditis, consider oral prednisolone.
  • First presentation or inflammatory exacerbation of left-sided or extensive ulcerative colitis:
    • High induction dose of an oral aminosalicylate
    • Consider adding a topical aminosalicylate or oral beclometasone dipropionate.
    • Oral prednisolone can be used for patients who cannot tolerate or who decline aminosalicylates, or if aminosalicylates are contra-indicated or for those who have subacute ulcerative colitis.

Inducing remission in children and young people

  • This relates to those with a mild-to-moderate first presentation or inflammatory exacerbation of left-sided or extensive ulcerative colitis:
    • Oral aminosalicylate.
    • Consider adding a topical aminosalicylate or oral beclometasone dipropionate.

Further treatments for all extents of mild-to-moderate disease:

  • Oral prednisolone can be added to aminosalicylate therapy to induce remission if there is no improvement within four weeks of starting aminosalicylate therapy or if symptoms worsen despite treatment. Stop beclometasone dipropionate if adding oral prednisolone.
  • Oral tacrolimus can be added to oral prednisolone to induce remission in people with mild-to-moderate ulcerative colitis if there is an inadequate response to oral prednisolone after 2-4 weeks.

Inducing remission for patients with acute severe ulcerative colitis
Adding IV ciclosporin to IV corticosteroids or surgery should be considered for people:

  • Who have little or no improvement within 72 hours of starting intravenous corticosteroids; or
  • Whose symptoms worsen at any time despite corticosteroid treatment.

Maintaining remission

  • A once-daily dosing regimen for oral aminosalicylates can be used for maintaining remission.
  • Local safety monitoring policies should be followed for patients receiving treatment that needs monitoring - eg, aminosalicylates, tacrolimus, ciclosporin, infliximab, azathioprine and mercaptopurine.
  • To maintain remission after a mild-to-moderate inflammatory exacerbation of proctitis or proctosigmoiditis:
    • A topical aminosalicylate alone (daily or intermittent); or
    • An oral aminosalicylate plus a topical aminosalicylate (daily or intermittent); or
    • An oral aminosalicylate alone (this may not be as effective as combined treatment or an intermittent topical aminosalicylate alone).
  • An oral aminosalicylate to maintain remission in children and young people after a mild-to-moderate inflammatory exacerbation of left-sided or extensive ulcerative colitis.
  • Oral azathioprine or oral mercaptopurine to maintain remission:
    • After two or more inflammatory exacerbations in twelve months that require treatment with systemic corticosteroids; or
    • If remission is not maintained by aminosalicylates.
  • To maintain remission after a single episode of acute severe ulcerative colitis:
    • Oral azathioprine or oral mercaptopurine; or
    • Oral aminosalicylates in people who cannot tolerate or who decline azathioprine and/or mercaptopurine, or in whom azathioprine and/or mercaptopurine are contra-indicated.


Up to 30% of patients will ultimately require colectomy for ulcerative colitis.[3] 

  • Colectomy is an option for patients who do not respond to, or are intolerant of, medical treatment, or in those with complications such as colorectal neoplasia.[15] 
  • Because ulcerative colitis is confined to the colorectum, colectomy is curative.[15] 
  • The usual procedure is a restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA).[15] 
  • There may be an increased likelihood of needing surgery for people with any of the following:[1] 
    • Stool frequency of more than eight per day.
    • Pyrexia.
    • Tachycardia.
    • An abdominal X-ray showing colonic dilatation.
    • Low albumin, low haemoglobin, high platelet count or CRP >45 mg/L.
  • Colorectal cancer:
    • Patients with ulcerative colitis have about double the incidence of colorectal cancer than people without the disorder.
    • However, recent population-based data suggest that the overall risk of colorectal cancer may be comparable to the general population, although patients with disease diagnosed in childhood and adolescence, with a longer disease duration or with co-existent primary sclerosing cholangitis seem to be at higher risk.
    • In the UK, colonoscopic surveillance is recommended for all patients, starting about ten years after the onset of symptoms, except for those with ulcerative proctitis that is documented on two consecutive endoscopic examinations, who do not require surveillance.[4] 
    • The surveillance interval depends on the extent of disease. See separate Screening for the Early Detection of Colorectal Cancer article.
    • The evidence base for this regime is not robust and NICE recommends further research in this area.[16]
  • Other bowel complications include:
    • Pouchitis: up to 45% of patients who undergo ileal pouch surgery for ulcerative colitis have pouchitis. Metronidazole or ciprofloxacin for two weeks is the first-line therapy. Mesalazine or corticosteroids may be used in acute pouchitis if antibiotics are ineffective. Long-term, low-dose metronidazole or ciprofloxacin are potentially effective for chronic pouchitis.
    • Post-IPAA complications include leakage and pelvic abscess.
    • Toxic megacolon may be triggered by hypokalaemia, opiates, anticholinergics and barium enemas. The colon becomes acutely dilated and patients are severely ill. IV fluids, IV steroids, antibiotics and IV ciclosporin are the mainstay of conservative treatment but total colectomy may be required.
  • Management of extra-intestinal manifestations: those that are associated with active intestinal disease largely respond to therapy aimed at controlling disease activity, whereas those that occur whether disease is inactive or quiescent, run a course independent of therapy for intestinal disease.
  • Osteoporosis:[4] 
    • This is common, although the absolute fracture risk, contribution of steroids and role of prophylaxis remain a subject for debate.
    • The use of corticosteroids should be minimised by optimising 5-ASA treatment and introducing thiopurines early in the disease course if 5-ASAs do not control disease activity.
    • In the UK, guidelines recommend bisphosphonate prophylaxis in patients aged over 65 years who need corticosteroids.
    • In patients aged under 65 years who need more than three months of glucocorticoids, bone densitometry measurement is recommended and a bisphosphonate started if the T score is 1.5 or less.
    • See separate Osteoporosis Risk Assessment and Primary Prevention article.
  • Psychosocial and sexual problems may arise.[17] 
  • Ulcerative colitis is a lifelong condition, with unpredictable relapses and remissions.
  • Mortality is slightly higher than in the general population.
  • One study in Norway found that:[18] 
    • The cumulative colectomy rate after ten years was 9.8%.
    • 83% of people initially had relapsing disease but half were relapse-free after five years.
    • About 20% of people with proctitis or left-sided colitis progressed to extensive colitis.
  • The prognosis for acute severe colitis depends on their initial response to corticosteroid treatment.

Further reading & references

  1. Ulcerative colitis: management; NICE Clinical Guideline (June 2013)
  2. Ulcerative colitis; NICE CKS, August 2014 (UK access only)
  3. Guidelines for the management of inflammatory bowel disease in adults; British Society of Gastroenterology (2011)
  4. Van de Vijver E, Schreuder AB, Cnossen WR, et al; Safely ruling out inflammatory bowel disease in children and teenagers without referral for endoscopy. Arch Dis Child. 2012 Dec;97(12):1014-8. doi: 10.1136/archdischild-2011-301206. Epub 2012 Sep 27.
  5. Collins P, Rhodes J; Ulcerative colitis: diagnosis and management. BMJ. 2006 Aug 12;333(7563):340-3.
  6. Fell JM et al BSPGHAN IBD working group; Management of ulcerative colitis, Archives of Disease in Childhood, 2016
  7. Leukapheresis for inflammatory bowel disease; NICE Interventional Procedure Guidance, June 2005
  8. Habermalz B, Sauerland S; Clinical effectiveness of selective granulocyte, monocyte adsorptive apheresis with the Adacolumn device in ulcerative colitis. Dig Dis Sci. 2009 Jun 11.
  9. Zhu M, Xu X, Nie F, et al; The efficacy and safety of selective leukocytapheresis in the treatment of ulcerative colitis: a meta-analysis. Int J Colorectal Dis. 2011 Aug;26(8):999-1007. Epub 2011 Apr 8.
  10. Oliveira L, Cohen RD; Maintaining remission in ulcerative colitis - role of once daily extended-release mesalamine. Drug Des Devel Ther. 2011 Feb 27;5:111-6.
  11. British National Formulary; NICE Evidence Services (UK access only)
  12. Yang LP, McCormack PL; MMX(R) Mesalazine: a review of its use in the management of mild to moderate Drugs. 2011 Jan 22;71(2):221-35. doi: 10.2165/11205870-000000000-00000.
  13. Hoentjen F, Sakuraba A, Hanauer S; Update on the management of ulcerative colitis. Curr Gastroenterol Rep. 2011 Oct;13(5):475-85.
  14. Infliximab for the treatment of acute exacerbations of ulcerative colitis; NICE Technology Appraisal Guidance, December 2008
  15. Ford AC, Moayyedi P, Hanauer SB; Ulcerative colitis. BMJ. 2013 Feb 5;346:f432. doi: 10.1136/bmj.f432.
  16. Colonoscopic surveillance for prevention of colorectal cancer in people with ulcerative colitis, Crohn's disease or adenomas; NICE Clinical Guideline (March 2011)
  17. Ochsenkuhn T, D'Haens G; Current misunderstandings in the management of ulcerative colitis. Gut. 2011 Sep;60(9):1294-9. Epub 2011 Apr 19.
  18. Solberg IC, Lygren I, Jahnsen J, et al; Clinical course during the first 10 years of ulcerative colitis: results from a population-based inception cohort (IBSEN Study). Scand J Gastroenterol. 2009;44(4):431-40. doi: 10.1080/00365520802600961.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Colin Tidy
Current Version:
Peer Reviewer:
Dr Adrian Bonsall
Document ID:
2898 (v27)
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