What the difference between anal fissure and anal fistula?

Tear vs pus: A fissure is a tear of the anal canal - hurts a lot when you have a bm. A fistula is a chronic perianal/rectal infection that resulted in the formation of a tunnel (variable depth and complexity) that is prone to infection complication. You need a surgeon's help for both conditions.

Surface vs deeper: A fissure is a surface crack in the skin at the anal opening. A fistula is a deeper tunnel under the skin or under the sphincter muscles. Fissure may be treated medically at first & fistula more likely to need surgery first.

Tear versus tunnel: An anal fissure is a tear in the lining of the anal canal, just inside the opening, and is characterized by painful bowel movements and rectal bleeding. An anal fistula is a tunnel from inside the anal canal out to the perinatal skin, resulting from a peri rectal abscess. It causes intermittent drainage and sometimes pain, swelling and bleeding.

All Different: Fissure: think paper cut in your anus hemorrhoids: think varicose veins in the anus fistula: much more complex - think aberrant tract from rectum to skin that shouldn't be there.

Tear / tract: A fissure is s a tear in the anal mucosa. A fistula is a tunnel deeper in the tissues with one opening on the outside and another opening on the inside of the anal canal or lower rectum.