The reason why perianal skin breaks down is due to the following reasons: first, perianal eczema, perianal eczema will form many small papules and granular bumps on the skin around the anus, and cause severe itching symptoms, scratching will cause the skin to break down, the reason why perianal eczema is mainly due to the long-term dampness of the environment around the anus and their own endocrine disorders. The second, perianal abscess, perianal abscess will form a mass around the anus, when the mass ruptures will form pollution of the surrounding skin, causing skin ulcers, forming fistulae in the perianal skin, perianal abscess is due to acute purulent lesions at the end of the rectum. Third, anal fissures, the initial onset of anal fissures will form fissures in the skin around the anus, when the fissures are infected with bacteria will be followed by skin breakdown.