How can a proctologist tell if it's a fissure fistula or a anal fissure?

Different: An anal fissure is superficial and wholly contained in the anus. A fistula is a tract that can connect the bowel to an adjacent organ, to the skin, or to itself. The proctologist will do a careful exam to probe the lesion and see if it is a fissure versus a fistula.

2 different things: A fissure is a tear in the tissue that lines the anal canal. The pain caused by this tear causes spasm which can worsen the fissure. A fistula on the other hand is a tunnel that usual runs from one of the rectal glands above the anus and tracks to the skin outside of the anus. Theses can leak or get plugged up causing abscesses. The treatments are different so make sure you understand which on.

Exam: Physical examination by a trained professional. Fissure is a crack or tear on the surface of the anal skin. A fistula is an infected tunnel running underneath the anal skin.