Anal fissure

Also called Tear in the anus

A small tear that causes pain out of all proportion to its size. Treating the constipation is what heals it, not creams alone.

What it is

A small tear in the lining of the anal canal, usually caused by passing a hard stool.

It is common and it is far more painful than its size suggests: severe, sharp pain on passing a stool, often followed by an aching burn lasting hours.

The reason it becomes chronic is a self-perpetuating loop. The pain causes the internal sphincter to go into spasm; the spasm reduces the blood supply to the tear; poor blood supply prevents healing; and the person then dreads opening their bowels, holds on, and the stool gets harder. Understanding that loop explains every part of the treatment.

Treatment therefore has to do three things at once: soften the stool, relieve the pain, and relax the sphincter, usually with a glyceryl trinitrate or diltiazem ointment. Most fissures heal within weeks with all three. Creams alone, without fixing the constipation, reliably fail.

Fissures in unusual positions, multiple fissures, or ones that will not heal need investigating for Crohn's disease, infection, or rarely cancer.

Signs you might notice

Sharp, severe pain on passing a stool, often described as passing glass, with a burning ache afterwards.

Bright red blood on the paper or on the surface of the stool, in small amounts.

Itching, and sometimes a visible tear or a small skin tag at the edge.

Fear of opening the bowels, and consequent constipation.

See a GP for: bleeding that is dark or mixed into the stool, any change in bowel habit lasting three weeks, weight loss, a lump, or bleeding in anyone over 50. Those point elsewhere, including to bowel cancer, and must not be assumed to be a fissure or haemorrhoids.

Also see a GP for a fissure not healing in six to eight weeks.

How it can affect day-to-day life

Embarrassment delays presentation more here than almost anywhere. People live with severe daily pain for months rather than say where it hurts.

The fear of the toilet becomes the main problem. Holding on hardens the stool and guarantees the next tear, so breaking the fear is part of treatment.

In children, a painful fissure is one of the commonest starting points for chronic stool withholding and constipation in children, and it needs treating quickly and gently.

The ointments commonly cause headaches, which is why people stop them. Starting with a smaller amount and taking paracetamol helps, and it usually settles within a week.

For anybody with reduced mobility, poor fluid intake, or on constipating medicines including opioids and iron, the fissure is a symptom of a bowel problem that needs managing continuously.

Supporting someone well

Soften the stool and keep it soft for at least six to eight weeks after the pain has gone. This is the treatment; the rest is support.

Fluids, fibre, and a laxative that softens rather than stimulates.

Do not delay going. Go when the urge comes.

Warm baths after opening the bowels relax the sphincter and relieve the pain.

Use the prescribed ointment for the full course, and persist through the headache.

Do not use over-the-counter haemorrhoid creams as a substitute; they do not address the spasm.

Check the medicines list for constipating drugs and ask whether anything can change.

Get it looked at if it has not healed in two months, rather than living with it.

Where to get help

A pharmacist for laxatives and initial advice.

A GP practice for prescription ointment, for a fissure that will not heal, and for any red flag symptoms.

Colorectal surgery for chronic fissures; treatments including botulinum toxin injection and surgery are effective.

Guts UK publish clear information on bowel symptoms.