Anal fissure
A fissure is a small tear in the lining of the anal canal, usually caused by passing a hard stool. It causes sharp, cutting pain during and after bowel movements, sometimes lasting for hours, with a streak of bright red blood.
Treatment
- Acute fissures (under 6 weeks) usually heal with stool softeners, high fibre, plenty of water, warm sitz baths and a local anaesthetic gel.
- Muscle-relaxing ointments (glyceryl trinitrate or diltiazem) relax the anal sphincter spasm and help healing in 6–8 weeks.
- Botulinum toxin (Botox) injection temporarily relaxes the sphincter for fissures that do not respond to creams.
- Lateral internal sphincterotomy (LIS) is a short procedure that divides a small part of the internal sphincter muscle. It heals more than 90% of chronic fissures; a small risk of minor incontinence to gas must be discussed.
Fistula-in-ano
A fistula is an abnormal tunnel between the inside of the anal canal and the skin near the anus. It almost always follows an anal abscess. Symptoms include recurrent painful swelling, and discharge of pus or blood from an opening near the anus that soils underwear.
A fistula will not heal with antibiotics alone. Surgery aims to cure the tunnel while protecting the sphincter muscles that control continence.
Assessment
Examination under anaesthesia and MRI fistulogram show the exact path of the tract and how much sphincter muscle it crosses. Fistulas are classed as simple (low) or complex (high, branching, recurrent, or associated with Crohn's disease).
Treatment options
- Fistulotomy: laying open a low fistula – success above 90% for simple tracts.
- Seton: a soft thread placed through the tract to drain infection, either as a first stage or long term.
- LIFT (ligation of intersphincteric fistula tract): closes the tract between the sphincter muscles without cutting them.
- Advancement flap: covers the internal opening with healthy tissue.
- VAAFT (video-assisted anal fistula treatment) and laser (FiLaC): sphincter-saving, minimally invasive techniques suitable for selected fistulas.
- Kshar sutra: a medicated thread used in Ayurvedic practice, working similarly to a cutting seton.
Recovery
Most fissure and simple fistula procedures are day-care. Sitz baths, stool softeners, painkillers and regular dressings help healing, which usually takes 2–6 weeks depending on the procedure.
Frequently asked questions
How do I know if it is a fissure or piles?
Severe cutting pain during stool usually suggests a fissure; painless bleeding or a lump suggests piles. An examination confirms it.
Can a fistula close on its own?
Very rarely. The tract is lined with tissue that keeps it open, so most fistulas need a procedure.
Will fistula surgery affect bowel control?
Sphincter-sparing techniques and careful planning keep this risk low. Discuss the trade-off between cure rate and continence with your surgeon.
Last reviewed: October 2026. This page is general information and does not replace advice from your own doctor.