The main causes include hemorrhoids, intestinal polyps, rectal mucosal prolapse, follicular inflammation, and warts.
1. Hemorrhoids: Hemorrhoids protruding from the anal opening are mainly external hemorrhoids, which are caused by varicose veins below the dentate line.
2. Intestinal polyps: Prolapse of polyps in the intestinal tract and their projection out of the anus will have corresponding changes.
3. Prolapse of rectal mucosa: prolonged constipation, resulting in increased abdominal pressure, can cause prolapse of rectal mucosa, prolapse of the anus will have corresponding changes.
4. Hair follicle inflammation: local hair follicle blockage caused by inflammation, will lead to tissue hyperplasia caused by corresponding changes, usually accompanied by redness, swelling and pain.
5. Condyloma acuminatum: caused by HPV virus infection, can cause local tissue around the anal opening to bulge, itching, tingling, and progressive growth.