The most common ones are mainly caused by internal hemorrhoids, rectal prolapse and anal fistula. When internal hemorrhoids patients develop to the fourth stage, the nucleus of the hemorrhoid prolapses outside the anus and cannot be returned, and the anal atresia is not tight, causing the mucus and stool in the rectum to leak out of the body, thus the phenomenon of anal uncleanliness. The prolapse of the rectum, especially in the case of prolapse, the rectal wall prolapses outside the anus, which also leads to a gap in the anal atresia and leakage of stool and mucus, and in the case of anal fistula, the most obvious is complete anal fistula, in which the secretions, stool and mucus in the rectum are directly discharged through the internal orifice, fistula and external orifice, resulting in the symptoms of long-term fecal contamination of the anus. In addition, some people may also have long-term fecal or moist unclean anal area due to the inability of the anal sphincter to fully control anal closure, or the increased local secretions of perianal eczema patients themselves.