What is Fistula?
An anal fistula is an abnormal channel between the anal canal (back passage) and the skin around the anal opening. It is associated with an abscess formation around the anus and is more common in men.
Aetiology and Risk Factors
The formation of an anal fistula typically occurs as a result of an anal abscess. About 25-50% of people with an anal abscess will develop an anal fistula. In rare cases, anorectal cancer can occasionally present with an anal fistula.
Another risk factors include:
* Inflammatory bowel disease including Crohn’s disease and ulcerative colitis
* Systemic diseases like tuberculosis, diabetes and HIV
* Past trauma to the anal region
* Past radiation therapy to the anal region