Ddx between Crohn's and UC by the following features of Crohn's :
- Small bowel involvement
- Rectal sparing
- Absence of rectal bleeding
- Segmental / symmetrical distribution
- Perianal disease
- Associated mass / fistulae
- Patchy lesions / apthoid (small ulcer occuring in groups), longitudinal, or serpiginous (wavy margin) ulcerations at endoscopy + cobblestone appearance
- Transmural disease or granulomas on biopsy
