An anal fissure is a small tear in the lining of the anal canal that causes sharp pain during bowel movements, often with minor bleeding. It is usually caused by passing a hard stool and frequently heals with dietary changes, stool softeners, and topical medication.
An anal fistula is a different condition. It is an abnormal tunnel that forms between the inside of the anal canal and the skin near the anus, most often after an untreated perianal abscess. Unlike a fissure, a fistula does not heal on its own and always requires surgical treatment.
