The genetics of isolated colonic Crohn's disease place it approximately midway between Crohn's disease with small intestinal involvement and UC, making a case for considering it as a separate condition. We have therefore systematically reviewed its epidemiology, pathophysiology and treatment. Key findings include a higher incidence in females (65%) and older average age at presentation than Crohn's disease at other sites, a mucosa-associated microbiota between that found in ileal Crohn's disease and UC, no response to mesalazine, but possibly better response to antitumour necrosis factor than Crohn's disease at other sites. Diagnostic distinction from UC is often difficult and also needs to exclude other conditions including ischaemic colitis, segmental colitis associated with diverticular disease and tuberculosis. Future studies, particularly clinical trials, but also historical cohorts, should assess isolated colonic Crohn's disease separately.
- CROHN'S COLITIS
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Contributors JMR initiated the review. JMR and SS performed the literature searches and together wrote the first draft. AE advised on the analysis and presentation of epidemiology data. All authors contributed to the writing of the manuscript and approved the final version of the manuscript.
Competing interests SS has received speaker fee from MSD, Actavis, AbbVie, Dr Falk Pharmaceuticals, Shire and received educational grant from MSD, AbbVie, Actavis and is an advisory board member for AbbVie, Dr Falk Pharmaceuticals, Janssen and Vifor Pharmaceuticals. JMR is or has been a member of advisory boards for Atlantic, Pharmacosmos, Procter and Gamble, Vifor and Dr Falk Pharmaceuticals, has received speaking honoraria from Abbott, Dr Falk Pharmaceuticals, Ferring, GlaxoSmithKline, Merck, Procter and Gamble, Schering Plough, Shire and Wyeth and with the University of Liverpool and Provexis UK, holds a patent for use of a soluble fibre preparation as maintenance therapy for Crohn's disease plus a patent pending for its use in antibiotic-associated diarrhoea.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement All relevant data are included in the article.