Perianal dampness is caused by increased discharge from the anal opening and has many causes, which can be physiological or pathological. To sum up, there are five causes as follows. One is that the sebaceous glands and sweat glands in the anal department secrete a lot, and the anus is deep between the two sides of the buttocks. This deep position is very unfavorable to the evaporation of sweat around the anus, especially for people with an obese body type, and the position of the anus is deeper, causing dampness around the anus. Some people also do not pay attention to the hygiene around the anus, which also causes the symptoms of increased secretion in the anal part; secondly, the anal sphincter is loose and weak in the elderly or frail people, resulting in poor anal closure and overflow of intestinal and anal fluids out of the anus, producing the symptoms of increased secretion; thirdly, severe anal fissures and anal fistulas with external mouths near the anus, which overflow out of the anus due to more inflammatory exudation and damp symptoms; fourthly, complete rectal prolapse III. It often happens that the anal sphincter is weak, and the whole rectum or mucosa prolapses out of the anus when walking or straining, and the fluid on the surface of the rectal mucosa will contaminate the skin around the anus, resulting in symptoms of large amount of secretion at the anal opening; fifth, anal eczema, herpes, and anal contact dermatitis, which are also factors that cause increased local secretion in the anus; if there are symptoms of dampness and scratching around the anus, you should go to the hospital in time.