If the intestinal mucosa in the lumen of the bowel is normal, but there is a localized swelling sensation in the anus, the first consideration is that it may be caused by hemorrhoids, and secondly, it may be related to the relaxation of the mucosa. Some patients with sinusitis may also have localized anal swelling. 1. hemorrhoids: the most common cause of anal swelling, when the hemorrhoidal nuclei increase in size, will repeatedly prolapse outside the anus, resulting in localized swelling of the anus, accompanied by pain and swelling, as well as anal swelling prolapse and other clinical symptoms. 2. Excessive relaxation of the rectal mucosa: cause prolapse of the rectal mucosa, causing patients with different degrees of distension and frequent bowel movements, mainly due to the local mucosal compression of the anal opening skin nerves. 3. Anal sinusitis: local anal crypts are stimulated by long-term inflammation can also cause anal distension and falling sensation, accompanied by local anal pain during defecation and more secretions. Enteroscopy normal anal swelling, there may be other reasons, it is recommended to go to the hospital for examination, clear cause of the treatment as prescribed by the doctor.