Table 6

Features favouring Crohn's disease over ulcerative colitis

Reliability/discriminant valueFeatureFigureEvidence levelReferences
1. ReliableGranuloma (non-cryptolytic)EL1a RGA11 25 36 63
Focal or patchy lamina proprial chronic inflammation (rather than continuous/diffuse)EL1a RGA5 11 18 36
Focal or segmental crypt distortion (rather than continuous/diffuse)3CEL1a RGA5 21 36
 Ileal involvementEL1b RGB5 64
Absence of features of ulcerative colitis5
2. Fairly reliableDecreasing proximal to distal gradient of changesEL1b RGB36
3. Limited or conflicting evidence*Disproportionate submucosal inflammationEL5 RGD5
Focal crypt abscessesEL5 RGD34
Focal cryptitisEL5 RGD5
4. Limited evidence from non-initial studiesNormal mucosal surfaceNA34
Segmental crypt atrophyNA21
Segmental mucin depletionNA21
  • *The evidence for these is conflicting or sparse. Focal cryptitis, in particular, can be seen in many other situations, including ulcerative colitis and infection.