How is colitis caused?

Colitis refers to colonic inflammatory lesions caused by various causes. It can be caused by bacteria, fungi, viruses, parasites, protozoa and other organisms, but also by allergies and physical and chemical factors. According to different causes, it can be divided into specific inflammatory lesions and non-specific inflammatory lesions. The former refers to infectious colitis, ischemic colitis and pseudomembranous colitis, etc., and the latter includes ulcerative colitis and Crohn disease of colon.