Chronic colitis

Chronic colitis is a chronic, recurrent, and multifocal disease involving the colon, sigmoid colon, and rectum as the sites of onset. It refers to inflammatory edema, ulceration, and bleeding lesions of the rectum and colon caused by various pathogenic factors. Symptoms include left lower abdominal pain, diarrhea, tenesmus, occasional mucus in stool, alternating constipation and diarrhea, with periods of improvement and worsening, being protracted and recurrent. Chronic colitis is usually classified according to the pathogenic cause into specific colitis, i.e., colitis with an obvious cause, and nonspecific colitis, i.e., colitis with an unknown cause.