Piles versus fistula: telling the difference
By Dr Wong Nan-Yaw, MBBS (NUS), FRCS (Edinburgh). Published . 3 min read.
Piles are swollen blood vessels that bleed or prolapse, and an anal fistula is a small tunnel from the bowel to the skin that leaks pus. Painless bright red bleeding points to piles, and repeated discharge after an abscess points to a fistula (NHS). Dr Wong Nan-Yaw, a colorectal surgeon in practice since 2008, tells them apart with a short examination.
What is the difference between piles and an anal fistula?
Piles are swollen tissue inside or around the anus, and a fistula is an abnormal channel that connects the anal canal to the skin. They feel different, look different on examination and need different treatment, so the table below sets the two side by side.
| Piles (haemorrhoids) | Anal fistula | |
|---|---|---|
| What it is | Swollen cushions of tissue and blood vessels | A small tunnel between the anal canal and the skin |
| Typical symptom | Painless bright red blood, a lump that comes down, itching | Repeated discharge of pus, a small opening on the skin, soreness |
| Common clue | Blood on the paper after a bowel movement | A previous painful abscess near the anus |
| Usually treated by | Fibre and fluids, banding, or surgery for large piles | Surgery, because it rarely heals on its own |
How do I tell which one I have?
Bleeding without much pain suggests piles. Persistent discharge, especially after a painful abscess, suggests a fistula. Symptoms overlap, so an examination is the only reliable way to tell them apart, and a scan is sometimes added for complex fistulas.
Do both need surgery?
Most piles do not need surgery, and most fistulas do. Piles often settle with fibre, fluids and a quick clinic procedure. A fistula rarely heals by itself because the tunnel stays open, so surgery to lay open or close it is usually advised, and earlier assessment tends to mean simpler treatment.
Sources
Medically reviewed by Dr Wong Nan-Yaw
MBBS (NUS), FRCS (Edinburgh). 33 years in medicine (since 1993), 23 years as an accredited specialist (since 2003) and 18 years in private practice at Mount Elizabeth (since 2008). Last reviewed 6 November 2026.
How this article is prepared
Statements are checked against the sources listed above. This article is general education and does not replace a consultation. It is reviewed and updated when guidance changes. In an emergency, call 995.