Ulcerative colitis

Last updated: September 11, 2023

Summarytoggle arrow icon

Ulcerative colitis is an inflammatory bowel disease (IBD) characterized by chronic mucosal inflammation of the rectum, colon, and cecum. Common symptoms include bloody diarrhea, abdominal pain, and fecal urgency. Laboratory findings typically show elevated inflammatory markers (e.g., ESR, CRP) and elevated fecal calprotectin. Although not required for diagnosis, the presence of perinuclear antineutrophil cytoplasmic autoantibodies (pANCA) is suggestive of ulcerative colitis. Definitive diagnosis requires endoscopy, which may show changes to superficial vascular patterns, friable mucosa, and erosions and/or ulcerations. 5-Aminosalicylic acids (e.g., mesalamine) are the mainstay of treatment for mild-to-moderate disease. Patients who experience severe episodes often require corticosteroids or other immunosuppressants to achieve remission. In distal colitis, medications may be administered rectally (e.g., via enema), whereas more proximal inflammation requires oral treatment. Proctocolectomy is curative and indicated in patients with complicated ulcerative colitis or dysplasia. Patients with ulcerative colitis are at increased risk of developing colorectal cancer and should undergo regular endoscopic surveillance.

Epidemiologytoggle arrow icon

  • Prevalence
    • Approximately 600,000 adults in the US are affected by ulcerative colitis. [1]
    • Ethnicity
      • Higher in White populations than in Black, Hispanic, or Asian populations
      • Highest among individuals of Ashkenazi Jewish descent
  • Peak incidence
    • 15–35 years of age [2]
    • Another smaller peak may be observed in individuals > 55 years of age. [3]
    • Similar for men and women [4]

Epidemiological data refers to the US, unless otherwise specified.

Etiologytoggle arrow icon

Risk factors [3][5][6]

Protective factors [5][6]

Classificationtoggle arrow icon

Classification of ulcerative colitis by disease extent [2]

The extent of disease is classified based on endoscopic findings.

Montreal classification for the extent of ulcerative colitis
Disease extent Mucosal involvement
Ulcerative proctitis (E1) Limited to the rectum
Left-sided ulcerative colitis (E2) Limited to the colon distal to the splenic flexure
Extensive ulcerative colitis (E3) Extends proximal to the splenic flexure

Classification of ulcerative colitis by severity [2][7]

There are several classification systems that can be used to assess disease severity. Criteria include:

American College of Gastroenterology ulcerative colitis activity index [2]
Criteria Severity of ulcerative colitis
Mild Moderate-to-severe Fulminant
Stools per day < 4

> 6

> 10
Frequency of blood in stool Intermittent Frequent Continuous
Fecal urgency Mild, occasional Often Continuous
Hemoglobin Normal < 75% of normal Transfusion required
ESR < 30 mm/hour > 30 mm/hour
CRP Elevated
Fecal calprotectin > 150–200 mcg/g
Mayo endoscopy score 1 2–3 3
Ulcerative colitis endoscopic index of severity 2–4 5–8 7–8
Truelove and Witts severity index [7][10]
Criteria Mild Severe
Bowel movements per day ≤ 4 ≥ 6
Amount of blood in stool Small amount Macroscopic blood
Temperature No fever ≥ 37.8°C (100.4°F)
Heart rate No tachycardia > 90 bpm
Hemoglobin No severe anemia ≤ 75% of normal
ESR ≤ 30 mm/hour > 30 mm/hour

Treatment recommendations by the ACG are based on the ACG ulcerative colitis activity index, while recommendations by the American Gastroenterological Association (AGA) are based on a combination of the Truelove and Witts severity index and the Mayo score for ulcerative colitis activity. There is significant overlap among the criteria used in all ulcerative colitis severity indices.

Pathophysiologytoggle arrow icon

The exact mechanism is unknown but studies suggest that ulcerative colitis is caused by abnormal interactions between host immune cells and commensal bacteria. [5][6]

The rectum is always involved in ulcerative colitis.

Clinical featurestoggle arrow icon

Intestinal symptoms

Extraintestinal symptoms of ulcerative colitis

PSC is often associated with inflammatory bowel disease, especially ulcerative colitis. However, only approximately 4% of patients with inflammatory bowel disease develop PSC.

“ULCCCERS:” Ulcers, Large intestine, Continuous/Colon cancer/Crypt abscesses, Extends proximally, Red diarrhea, and Sclerosing cholangitis are the characteristics of ulcerative colitis.

Disease course

  • Chronic intermittent
    • Most common course
    • Exacerbation is followed by complete remission.
  • Chronic continuous
    • Complete remission does not occur.
    • Disease severity varies.
  • Acute fulminant

Subtypes and variantstoggle arrow icon

Backwash ileitis

Diagnosticstoggle arrow icon

Approach [2][13]

Laboratory studies [2][13]

Stool testing for causes of gastroenteritis is indicated in all patients. Blood tests are not routinely required for diagnosis but help assess disease activity and severity.

Diagnosis of ulcerative colitis does not require the measurement of CRP, ESR, or hemoglobin levels but they are used to determine disease severity.

Hypoalbuminemia and elevated CRP suggest a poor prognosis. Other poor prognostic factors include < 40 years of age at diagnosis, extensive ulcerative colitis, and severe disease based on endoscopic evaluation scores. [14][15]

Endoscopy [2][4]

Endoscopic findings in ulcerative colitis
Early stages Chronic disease
  • Loss of mucosal folds
  • Loss of haustra
  • Strictures
  • Deep ulcerations
  • Pseudopolyps
    • Raised areas of normal mucosal tissue that result from repeated cycles of ulceration and healing
    • Ulceration formation of granulation tissue → deposition of granulation tissue → epithelialization
    • Morphologically resemble polyps but do not undergo neoplastic transformation
    • Found in advanced disease

Patients with severe ulcerative colitis have a high risk for colonic perforation; therefore, caution should be used when performing biopsies.

Imaging [2][16]

Imaging studies are not routinely recommended; for diagnosing ulcerative colitis but may be used as an adjunct to endoscopy, particularly for the detection of complications; , or if endoscopy is not possible. [4]

Abdominal x-rays [2][4][17]

  • Indication: initial and serial evaluation of suspected ASUC
  • Findings
    • Typically normal in mild-to-moderate disease
    • Loss of colonic haustra (lead pipe appearance) may be seen in severe cases
    • May show signs of complications, e.g.:

CT or MRI abdomen [18]

  • Indications
    • Patients with abdominal symptoms that cannot be explained by the disease activity seen on endoscopy
    • To evaluate for:
  • Findings
    • Loss of haustra
    • Increased bowel wall thickness
    • Mural hyperenhancement
    • Signs of complications (similar to abdominal x-ray findings)

Barium enema radiography [17]

The role of barium enema is limited, as it is less sensitive than other imaging modalities and is contraindicated in patients with obstruction or perforation.

Abdominal ultrasound [17][18]

  • Indication: monitoring disease activity and treatment response
  • Findings: increased bowel wall thickness

Pathologytoggle arrow icon

Gross pathology

See “Endoscopic findings in ulcerative colitis” in “Diagnostics.”

Histological findings

In ulcerative colitis, the extent of intestinal inflammation is limited to the mucosa and submucosa. In contrast, Crohn disease shows a transmural pattern of intestinal involvement.

Noncaseating granulomas are seen in Crohn disease but are not a feature of ulcerative colitis!

Differential diagnosestoggle arrow icon

Differential diagnosis considerations

Microscopic colitis [19][20]

The differential diagnoses listed here are not exhaustive.

Treatmenttoggle arrow icon

Approach [2]

  • Choose medical therapy based on disease severity and disease extent.
  • If remission is achieved, initiate maintenance therapy.
  • If remission is not achieved, escalate treatment.
  • Monitor for complications related to the disease and treatment.
  • Consult surgery for consideration of curative proctocolectomy if medical therapy is unsuccessful or complications occur.
  • Screen for colorectal cancer and other common comorbidities (e.g., depression and anxiety).

While many patients with ulcerative colitis can be managed in an outpatient setting, patients with ASUC should be managed in the inpatient setting.

Management of acute severe ulcerative colitis

Avoid NSAIDs, opioids, and anticholinergic medications in patients with ASUC.

Neither total parenteral nutrition nor empiric antibiotics are routinely indicated in ASUC.

Pharmacological therapy [2]

  • Pharmacological therapy is used to induce and maintain disease remission.
  • Goals of treatment
    • Initially: symptomatic remission [2]
    • Long-term: mucosal healing

Induction of remission

While treatment recommendations are based on mild-to-moderate, moderate-to-severe, and acute severe disease severity, the ACG ulcerative colitis activity index classifies disease severity as mild, moderate-to-severe, or fulminant.

Medications for induction of remission in ulcerative colitis [2][4][14][15]
Disease severity Medications
Acute severe ulcerative colitis

Systemic corticosteroids should only be used for induction of remission. Steroid-sparing agents are preferred for maintenance of remission. [2]

Azathioprine may be considered in combination with anti-TNF therapy for induction of remission or as monotherapy for maintenance of remission; it is not recommended as monotherapy for induction of remission. [2]

Overview of 5-ASA and 5-ASA derivatives [2][14]

5-ASA and 5-ASA derivatives
Description Mechanism of action Adverse effects
  • 5-ASA alone (usually well-tolerated)
  • 5-ASA bound to sulfapyridine as a carrier
  • May be used in patients with ulcerative colitis with inflammatory arthritis
  • Metabolized to sulfapyridine and mesalamine by colonic bacteria
  • Sulfapyridine: antibacterial; responsible for most of the adverse effects
  • Sulfapyridine has proven to have beneficial effects in patients with rheumatic disease.

Supportive therapy [2]

Surgical treatment [2]

Ulcerative colitis can be cured surgically. Surgical treatment also reduces the risk of colorectal cancer.

Poor nutritional status prior to colectomy in ulcerative colitis is associated with adverse patient outcomes. Optimize nutritional status prior to surgery.

Long-term management

  • Disease monitoring
    • Assess treatment response using endoscopy or fecal calprotectin if endoscopy is not possible. [2]
    • Flexible sigmoidoscopy is recommended 3–6 months after starting a new treatment. [4]
    • Follow-up every 3 months until remission has been achieved, then every 6–12 months. [4]
  • Colorectal cancer screening [2][26]
    • Start screening 8–10 years after the initial diagnosis or at the time of diagnosis of PSC.

Complicationstoggle arrow icon


We list the most important complications. The selection is not exhaustive.

Special patient groupstoggle arrow icon

Inflammatory bowel disease in pregnancy [27][28]

Fertility and preconception counseling

  • Fertility is not affected in women with IBD in remission and no history of abdominal surgery.
  • Women with active disease have decreased fertility rates.
  • Pharmacological therapy for IBD does not impact fertility.
  • Active disease at conception increases the risk of persistently active disease during gestation.
  • Active disease is associated with an increased risk of preterm birth and low birth weight.
  • Patients who wish to conceive should be on appropriate pharmacological therapy to maintain disease remission.
  • With the exception of methotrexate, all other treatments can be continued at conception.

Disease management during pregnancy

Prognosistoggle arrow icon

On average, the life expectancy of patients with ulcerative colitis is normal.

Referencestoggle arrow icon

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