Table 5

Features favouring ulcerative colitis over Crohn's disease

Reliability/discriminant valueFeatureFiguresEvidence levelReferences
1. ReliableDiffuse crypt abnormalities within and between sites3CEL1a RGA13 18 36
Diffuse crypt abnormalities within a siteEL1b RGB18
Crypt atrophy2DEL1a RGA11 25 34 36 50 62
Abnormal crypt architectureEL1a RGA11 25 63
Villous or irregular mucosal surfaceEL1a RGA11 25
Mucin depletionEL1a RGA3 11 36 63
Absence of ileal inflammation3CEL1b RGB64
2. Reliable in some studies, but variably definedDiffuse transmucosal chronic inflammation/diffuse inflammation/heavy diffuse transmucosal lamina proprial infiltrate/transmucosal lamina proprial hypercellularity2FEL1b RGA3 11 36 50
3. Less evidenceWidespread cryptitis/‘general crypt epithelial polymorphs’EL1b RGD3 36 50
The following more prevalent distally than proximally: diffuse transmucosal inflammation; diffuse crypt changes; focal crypt changesEL2b RGC36