The anal fistula skin band dropped is a big hole may belong to the normal phenomenon, also does not exclude is infected or anal fistula recurrence caused by. 1. Normal phenomenon: anal fistula itself has inflammation and infection, anal fistula hanging line treatment does not need to be cut, after the skin band fell, the original infection site may form a hole, is a normal performance. With the passage of time, the hole will gradually heal and become smaller, until it disappears. 2. Infection: If an infection occurs during the treatment process, causing the skin in the area to become pus-filled and break down, there may be a hole in the eye after the surgery. It may also be accompanied by inflammatory secretions, local redness and pain. 3. anal fistula recurrence: anal fistula has a certain probability of recurrence, such as surgical treatment is not complete or wound deformity, etc., if accompanied by anal moisture, itching and pain and other symptoms, need to be vigilant has recurred. Because of the complexity of the cause, the patient is best to go to the hospital anorectal department, do a systematic examination to clarify the diagnosis, if there is an abnormality as soon as possible to give reasonable treatment.