Understanding the condition
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.
How it is assessed
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 is surgery considered?
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.
Surgery and important 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 and follow-up
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. Pain should steadily reduce, although complete healing can take several weeks. Return to work depends on symptoms and the procedure.
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.