External anal bulge may be associated with external hemorrhoids, rectal prolapse, anal papilloma and other causes, which require further differential diagnosis by a doctor. 1. External hemorrhoids: Patients with external hemorrhoids may experience swelling, itching or pain around the anus with bleeding, manifesting the appearance of an external anal bulge. 2. Rectal prolapse: the anal canal, rectum or even the lower intestinal wall of the sigmoid colon or the whole layer, may be displaced downward and prolapse outside the anus, causing external anal bulge. 3. Anal papilloma: the anal papilla due to feces and chronic inflammation of long-term stimulation and appear to increase, harden, with the development of the disease, can be with defecation and prolapse outside the anus, the phenomenon of anal bulge. It is recommended to go to the hospital in time, to clarify the cause of the disease, and to carry out standardized treatment under the guidance of the doctor, so as not to delay the condition.