Complications of collagenous colitis

Table 1 Comparative features of collagenous colitis (CC) with ulcerative colitis (UC) and Crohn’s disease (CD)

	CC	UC	CD
Usual age at diagnosis	Mid to older age, most over 40	Youth to middle age	As for UC, most under 40
Sex predominance	Usually female	Similar	Similar
Diarrhea	Watery	Usually bloody	Watery, sometimes with blood
Distribution in colon	Patchy, rare rectal sparing	Continuous with rectal involvement	Patchy or focal; some with rectal sparing
Mucosal involvement	Yes, with	Yes	Yes, with granulomas
Small bowel disease	Occurs; also celiac disease	“So-called ‘reflux’ ileitis with severe pancolitis”	Common, especially ileum
Complicating cancer	To date, no increased frequency	“Increased rates with extensive disease”	“Increased rates with extensive disease; small bowel cancer”
Autoimmune disorders	Yes	Yes	Yes