Table 1.

Score for histological assessment of ulcerative colitis

No significant inflammation	Mucosa free from active inflammation; no erosions or crypt abscesses; surface and glandular epithelial cells intact; general architecture of the mucosa often disturbed; edema and fibrosis of the lamina propria with occasional foci of lymphocytes
Mild to moderate inflammation	Epithelium usually intact; Glandular tubules irregularly arranged and often showing increased proliferative activity; Edema, vascular congestion, and interstitial hemorrhage presented in the lamina propria; Lymphocytes, plasma cells, and eosinophils increased in number, neutrophils often present, but less numerous than in the more severely affected specimens; Variation in intensity of inflammatory change in individual specimens giving a range of appearances from relatively quiescent to active inflammation
Severe inflammation	Mucosal surface often irregular due to edema, interstitial, hemorrhage, or inflammatory exudate in the lamina, propria; Small epithelial breaches common, sometimes with frank erosions and purulent exudate; Neutrophils and eosinophils passing through the damaged epithelium; Areas of flattened and cuboidal cells especially found near erosions; Mucosa showing heavy interstitial infiltration by lymphocytes, plasma cells, eosinophils and neutrophils; Glandular abnormalities (neutrophilic invasion of the tubules, epithelial focal degeneration and shedding of necrotic/viable cells into the glandular lumina; crypt abscesses (neutrophils, eosinophils, and epithelial debris); Sometimes, breaking down of the wall of the tubule with inflammatory exudate passing from the tubule into the lamina propria

Adapted from Truelove et al[23], 1956.