Background/aims: Rectal biopsy specimen changes distinguish acute self-limited colitis (ASLC) from idiopathic inflammatory bowel disease (IBD). This study aimed to determine whether these histological criteria are also valid for acute-onset IBD.
Methods: Blind analysis of colorectal biopsy specimens from 52 patients with ASLC, 51 patients with acute-onset (< 3 months) IBD, and 30 patients with chronic IBD was performed.
Results: Histological features of ASLC are normal crypt architecture and acute lamina propria inflammation, but mixed acute and chronic inflammation can be found. Histological features of IBD are diffusely abnormal crypt architecture, crypt atrophy, mixed lamina propria inflammation, basal plasmacytosis, basal lymphoid aggregates, basal lymphoid hyperplasia, isolated giant cells, epithelioid granulomas, goblet cell mucus depletion, and reactive epithelial hyperplasia. Changes of chronic IBD were present in biopsy specimens as early as 7 days after the onset of symptoms.
Conclusions: Rectal biopsy specimens are useful in distinguishing ASLC from acute-onset IBD even if the biopsy specimens are not obtained during the first 4 days of the illness. There were no significant differences in histology between acute-onset and chronic IBD.