There are many ways to form a fistula, commonly in the following areas, including infection, acquired factors, etc., as follows: 1. Infection, when the local tissue has an infection will form a lot of purulent fluid or inflammatory fluid, this fluid will flow around along the body’s tissue gaps or pipes formed later in life, this will form a fistula, if the opening of the fistula is on the skin, the local will have a significant The first thing you need to do is to get a new one. When a fistula is found, it needs to be treated in the hospital as soon as possible to prevent aggravation of the condition.