I think I have an anal fistula; which type of doctor should I make an appointment with?

Colorectal surgeon. Colon and rectal surgeon. No one else. Go to www.fascrs.org and look at the "locate a colon and rectal surgeon" tab and find someone near you. All best!
Colorectal Surgeon. A board certified colon and rectal surgeon has extensive training and experience in the management of anal fistulae.