Quick answer: An anal fissure is a small tear that commonly causes sharp pain during bowel movements and bright red bleeding. Treatment usually starts with keeping stools soft and prescribed medicines; persistent symptoms may need specialist assessment. Constant throbbing pain, swelling or fever may indicate an abscess rather than a fissure. See proctology assessment and treatment options NHS anal fissure guidance.
What is it?
A small tear in the lining of the anal canal causing severe pain on passing stool and sometimes bright red bleeding.
Conservative treatment
High-fibre diet, plenty of water, warm sitz baths, topical glyceryl trinitrate or diltiazem ointment for 6–8 weeks.
When surgery is needed
Chronic fissure resistant to medical therapy.
Surgical options
Lateral internal sphincterotomy (gold standard) or botulinum toxin injection. Day-care procedures with excellent outcome.
Prevention of recurrence
Maintain fibre and fluid intake; avoid straining.