| Ulcerative colitis | Crohn disease | |
|---|---|---|
| Location | Pancolitis (30%) Proctosigmoiditis (50%) Includes PSC (5%) |
Terminal ileum (80%) Ileocolonic (50%) Isolated ileal (30%) Isolated colonic (20%) |
| Distribution | Continuous from rectum | Skip lesions, often rectum-sparing |
| Histology | Mucosal inflammation without granulomas | Transmural inflammation, granulomas, cobblestone |
| Serology | p-ANCA | Anti-Saccharomyces cervisiae IgG |
| Complications | Toxic megacolon Colorectal cancer |
Intraabdominal abscess, perforation, fistulae, strictures, perianal disease, obstruction, colorectal cancer |
Extraintestinal Manifestations
- MSK
- Dermatologic
- Opthalmologic
- Clubbing
- Renal
- Hepatobiliary
- Hematologic
- Aphthous ulcers
Arthritis
Type 1: Pauciarticular
- <5 joints
- Large joints
- Short duration
- Correlates with disease activity
Type 2: Polyarticular
- >5 joints
- Small joints
- Months to years
- Independent of disease activity
Differential Diagnosis
- Infectious mimics (see below)
- Radiation colitis
- Diversion colitis
- Solitary rectal ulcer syndrome
- Graft versus host disease
- Diverticular colitis
- Medication-induced colitis, including NSAIDs, retinoic acid, checkpoint inhibitors, mycophenolate, and gold
- CVID
Colitis or Ileitis
- Bacterial: Shigella, enterohemorrhagic Escherichia coli, enteroinvasive Escherichia coli, Campylobacter jejuni, Salmonella, Yersinia enterocolitica, Mycobacterium tuberculosis, Clostridioides difficile, Vibrio parahaemolyticus, Chlamydia trachomatis (lymphogranuloma venereum)
- Parasitic: Entamoeba histolytica, Schistosoma, Balantidium coli, Trichinella spiralis
- Viruses: cytomegalovirus
