Anal fistula is a rare disease and a consequence of the abscess that spreads in the anus. The fistula itself is a tube that directly leads from the anal canal to the small opening of the skin near the anal opening.
Permanent discharge (watery pus) through this small opening irritates the skin and can cause discomfort and itching. Abscess can be painful in some cases. In very rare cases, anal fistula may be a sign of Crohn’s disease and even colon cancer. Fistula is usually treated with a minor operation: the fistula opens, the abscess is thoroughly cleansed, and the wound is tended so that the opening is healed and closed.