Symptoms

Symptoms of an anal fistula

Symptoms of an anal fistula can include:

• skin irritation around the anus
• a constant, throbbing pain that may be worse when you sit down, move around, have a bowel movement or cough
• smelly discharge from near your anus
passing pus or blood when you poo
• swelling and redness around your anus and a high temperature (fever), if you also have an abscess
• difficulty controlling bowel movements (bowel incontinence) in some cases

The end of the fistula might be visible as a hole in the skin near your anus, although this may be difficult for you to see yourself.

When to get medical advice

See your GP if you have persistent symptoms of an anal fistula. They will ask about your symptoms and whether you have any bowel conditions.

They may also ask to examine your anus and gently insert a finger inside it (rectal examination) to check for signs of a fistula.

If your GP thinks you might have a fistula, they can refer you to a specialist called a colorectal surgeon for further tests to confirm the diagnosis and determine the most suitable treatment.

These may include:

• a further physical andrectal examination
• a proctoscopy where a special telescope with a light on the end is used to look inside your anus
• an ultrasound scan, magnetic resonance imaging (MRI) scan, or computerised tomography (CT) scan