What anal fistula is?

Anal Fistula

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.

Classification of the disease

Simple or complex – depending on whether there is a single fistula tract or interlinking connections

Low or high – depending on its position and how close it is to the sphincter muscles (the rings of muscles that open and close the anus)

Causes 

Bursting of anal abscess 

Inflammatory bowel disease (IBD) or diverticulitis.

An anal fistula affects:

as many as 50% of people with Crohn’s disease

up to 30% of people with HIV (a virus that attacks the body’s immune system)

approximately 30-50% of people with an anal abscess (this is slightly more common in women than men)

Symptoms

The common symptoms of an anal fistula include:

skin irritation around the anus

a throbbing, constant pain that may be worse when you sit down, move around, have a bowel movement or cough

a discharge of pus or blood when having a bowel movement (rectal bleeding)

Treatment

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.

There is a risk of complications after anal fistula surgery, including:

Infection

Bowel incontinence and

Recurrent anal fistula