What is an anal fissure?
A fissure often follows a hard stool, although repeated loose stools can also injure the lining. Pain causes spasm of the internal anal muscle, which reduces blood flow and delays healing. Bright red blood may appear on toilet paper or the stool surface.
A persistent fissure can develop a small skin tag or exposed muscle fibres. A fissure away from the usual midline position, or more than one fissure, needs assessment for another condition.
What are the symptoms of an anal fissure?
Common symptoms are:
- Sharp, tearing pain while passing stool
- A burning ache that can last for hours afterwards
- Bright red blood on the toilet paper or on the stool
- A small skin tag at the anal edge when a fissure has lasted a long time
How is an anal fissure diagnosed?
A careful history and gentle inspection usually establish the diagnosis. A very painful fissure should not be forced open for examination. The surgeon also asks about constipation, diarrhoea, childbirth injury, previous anal surgery and any existing difficulty controlling gas or stool.
These details are important because treatment must heal the fissure without causing a continence problem.
When does an anal fissure need surgery?
Initial treatment keeps the stool soft and relaxes the internal anal muscle with prescription ointment and warm sitz baths. A topical calcium-channel blocker usually causes fewer headaches than glyceryl trinitrate.
Surgery is considered for a typical chronic fissure that remains painful despite an adequate course of treatment. Existing leakage, childbirth-related muscle injury, inflammatory bowel disease and previous anal surgery may favour a sphincter-preserving approach.
How is fissure surgery done, and what are the risks?
Lateral internal sphincterotomy divides a carefully measured part of the tight internal muscle and heals most typical chronic fissures. Tailoring the division to the fissure limits injury to the muscle. A flap procedure covers the fissure without dividing the sphincter and may suit patients at higher continence risk.
Risks include bleeding, infection, recurrence and a change in control of gas or stool. The procedure should be chosen after a continence-aware assessment rather than on speed or technology labels.
Recovery after fissure treatment
Continue stool-softening measures and prescribed pain relief. Sit in a warm sitz bath (a tub of plain warm water) for 10–15 minutes, 2–3 times a day and after passing stool. After sphincterotomy, most people go home the same day or the next morning. The sharp pain with motions usually eases within a few days, desk work is possible in about a week, and the fissure heals fully in 4 to 6 weeks.
Seek review for fever, swelling, pus, escalating pain, heavy bleeding or new leakage. Persistent symptoms may mean the fissure has not healed or another diagnosis needs consideration.
When to seek urgent care
Seek prompt assessment for fever, spreading redness, pus, a tender swelling, inability to pass urine, heavy bleeding or rapidly worsening pain. These signs may indicate an abscess or another condition rather than a simple fissure.