What are the differences between Crohn's disease (CD) and Ulcerative colitis (UC)?

Crohn's disease (CD) Vs Ulcerative colitis (UC)


The differences between Crohn's disease (CD) and Ulcerative colitis (UC)


Crohn's disease (CD)

Ulcerative colitis (UC)


Slight female preponderance

Male and female are equally affected

Ethnic group

Any; more common in Ashkenazi Jews

Any groups

Risk factors

More common in smokers

·  More common in non-smoker and ex-smokers.

·  Appendicectomy protects


·  Diarrhea usually non-bloody.

·  Weight loss more prominent.

·  Upper GI symptoms, mouth ulcers.

·  Perianal disease.

·  Abdominal mass palpable in the right iliac fossa.

·  Bloody diarrhea more common.

·  Tenesmus.

·  Abdominal pain in the left lower quadrant.


·  Gallstones are more common secondary to reduced bile acid reabsorption.

·  Oxalate renal stones.

·  Primary sclerosing cholangitis (PSC) more common

Anatomical distribution

·  Lesions may be seen anywhere from the mouth to anus.

·  Perianal diseases are common

·  Skip lesions may be present.


·  Colon only; Inflammation always starts at rectum and never spreads beyond ileocecal valve.

·  Continuous disease.


Associated antibody

Associated with ASCA (Anti- Saccharomyces Cerevisiae Antibodies)

Associated with pANCA


·  Inflammation in all layers from mucosa to serosa with patchy changes.

·  Non-caseating granulomas.


·  No inflammation beyond submucosa (unless fulminant disease) - inflammatory cell infiltrate in lamina propria

·  Neutrophils migrate through the walls of glands to form crypt abscesses.

·  Depletion of goblet cells and mucin from gland epithelium.

·  Granulomas are infrequent.


Small bowel enema

·  High sensitivity and specificity for examination of the terminal ileum.

·  Strictures: 'Kantor's string sign'.

·  Proximal bowel dilation.

·  'Rose thorn' ulcers.

·  Fistulae (e.g. colovesical)

Barium enema

·  Loss of haustrations

·  Superficial ulceration, 'pseudopolyps'

·  Long standing disease: colon is narrow and short -'drainpipe colon'


·  Deep fissuring ulcers, fistulae

·  Skip lesions

·  'Cobble-stone' appearance.

·  Widespread ulceration with preservation of adjacent mucosa which has the  appearance of polyps ('pseudopolyps')


·  Glucocorticoids; azathioprine; methotrexate; biological therapy

(anti-TNF, anti-α4β7 integrin); nutritional therapy;

·  Smoking cessation

·  Surgery for complications is not curative

·  5-ASA is not effective

·  5-ASA; glucocorticoids; azathioprine; biological therapy (anti-TNF, anti-α4β7 integrin);

·  Colectomy is curative


Obstruction, fistula, anal tags, colorectal cancer.

Risk of colorectal cancer high in

UC than CD.


Additional: Common pattern of disease distribution along with histology of both CD and UC

Crohn's disease (CD) and Ulcerative colitis (UC)


  • Step Up to MRCP Review Note for Part I & Part II by Dr Khaled El Magraby; page: 303
  • Davidsons Principles and Practice of Medicine 23 edition; page: 814

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