What is Anal Fistula?

An anal fistula is an infected tunnel that runs between the skin and the anal opening. This is usually the result of an infection that originates in an anal gland and causes an abscess – a swollen pocket of infected tissue and fluid. The fistula forms a tunnel under the skin and connects with the infected gland.

The small glands inside the anus produce mucous and occasionally become infected. Infections that don’t heal in the right manner can lead to an anal fistula.