Scoring system for histological assessment (modified from D’Haens and colleagues9)
| Epithelial damage | 0 | Normal |
| 1 | Focal pathology | |
| 2 | Extensive pathology | |
| Architectural changes | 0 | Normal |
| 1 | Moderately disturbed (<50%) | |
| 2 | Severely disturbed (>50%) | |
| Infiltration of mononuclear cells in the lamina propria | 0 | Normal |
| 1 | Moderately increase | |
| 2 | Severely increase | |
| Infiltration of polymorphonuclear cells in the lamina propria | 1 | Normal |
| 2 | Moderately increase | |
| 3 | Severely increase | |
| Polymorphonuclear cells in epithelium | 0 | In surface epithelium |
| 1 | Cryptitis | |
| 2 | Crypt abscess | |
| Presence of erosions and/or ulcers | 0 | Yes |
| 1 | No | |
| Presence of granuloma | 0 | Yes |
| 1 | No | |
| No of biopsy specimens affected | 0 | None (0/3) |
| 1 | ≤33%(1/3) | |
| 2 | 33–66% (2/3) | |
| 3 | >66% (3/3) |