Crohn's Disease vs. Ulcerative Colitis: Two Types of IBD

Crohn's disease and ulcerative colitis are the two main types of inflammatory bowel disease (IBD). While both cause chronic GI inflammation, they differ in location, depth of inflammation, and complication patterns. Accurate diagnosis guides treatment strategy.

Key Differences at a Glance

Location
Crohn's Disease
Can affect any part of GI tract (mouth to anus), commonly terminal ileum
Ulcerative Colitis
Limited to the colon and rectum
Pattern
Crohn's Disease
Skip lesions — patches of disease with normal tissue between
Ulcerative Colitis
Continuous inflammation starting from the rectum upward
Depth
Crohn's Disease
Transmural — involves full thickness of bowel wall
Ulcerative Colitis
Mucosal — only the innermost lining
Complications
Crohn's Disease
Fistulas, strictures, abscesses
Ulcerative Colitis
Toxic megacolon, increased colon cancer risk

Shared Symptoms

  • Abdominal pain
  • Diarrhea
  • Bloody stools
  • Fatigue
  • Weight loss
  • Fever

Unique Indicators

ONLY Crohn's Disease
  • Perianal disease (fistulas, abscesses)
  • Mouth ulcers
  • Right lower quadrant pain
  • Malabsorption
ONLY Ulcerative Colitis
  • Continuous rectal bleeding
  • Urgency and tenesmus
  • Left-sided abdominal pain

Professional Diagnosis

Colonoscopy with biopsy is essential for both. CT enterography or MRI enterography evaluates small bowel involvement in Crohn's. Blood and stool inflammatory markers support the diagnosis.

Treatment for Crohn's Disease

5-ASAs (limited role), corticosteroids for flares, immunomodulators (azathioprine), biologics (anti-TNF, anti-integrins, anti-IL-12/23), and surgery for complications.

Treatment for Ulcerative Colitis

5-ASAs (mesalamine — effective as maintenance), corticosteroids for flares, immunomodulators, biologics, and colectomy as a curative option for refractory disease.

When to See a Doctor

See a gastroenterologist for persistent bloody diarrhea, unexplained weight loss, or chronic abdominal pain. Seek emergency care for severe abdominal distension, high fever, or profuse bleeding.

Not sure which one you have?

Try our free AI Symptom Checker for an instant personalized analysis.

Medically Reviewed for Accuracy

Medical Advisory Board
Last reviewed: March 20, 2026

Content is aligned with established clinical guidelines from authoritative medical institutions, including MedlinePlus (U.S. National Library of Medicine), the CDC, the NIH, and the NHS. All content is reviewed by our medical advisory board for accuracy and safety.