If anal swelling is found after intercourse, the possible causes are rectal and perianal lesions, and intercourse will lead to an increase in local perianal pressure, resulting in more obvious symptoms of some lesions, mainly due to rectal and perianal related lesions, as follows: 1. rectal inflammation: inflammation of the rectum can be caused by bacterial infection or viral infection. 2. autoimmune enteritis: such as ulcerative 3, hemorrhoids: especially when hemorrhoids combined with infection is more likely to appear. 4, malignant tumors: anal swelling may be caused by malignant tumors of the rectum, especially rectal cancer or anal canal cancer caused. If you find anal swelling after intercourse, it is recommended to go to a regular specialist hospital for systematic examination and clear diagnosis.