An anal fistula is a small channel that develops between the end of the bowel, known as the anal canal, and the skin near the anus.
The end of the fistula can appear as a hole in the skin around the anus. The anus is the opening where waste leaves the body.
Anal fistulas are usually classed as either:
The common symptoms of an anal fistula include:
You should see your GP if you have any of these symptoms. You may be referred to a specialist in bowel conditions, known as a colorectal surgeon, for further investigation.
Read more about diagnosing an anal fistula.
An anal fistula usually develops after an anal abscess (a collection of pus) bursts, or when an abscess has not been completely treated.
An anal fistula affects:
Read more information about the causes of an anal fistula.
Most anal fistulas require surgery because they rarely heal if they are not treated. Several surgical methods are available, depending on where the fistula is and whether it is classed as simple or complex.
You may be able to go home on the day of surgery. However, you may need to stay in hospital for a few days if the fistula is difficult to treat.
There is a risk of complications after anal fistula surgery, including:
For example, after the most common type of surgery for a fistula (known as a fistulotomy), the risk of an anal fistula coming back is around 21%.
The risks vary depending on the type of procedure. You can discuss this with your surgeon.
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