Anal fissure

Last updated:

Reviewed by:

Dr Rhianna McClymont

, Lead GP at Livi

Medically reviewed

An anal fissure is a small tear or ulcer in the thin tissue lining the large intestine, close to the anus. It typically causes pain and bleeding during bowel movements. We look at the causes of anal fissures and outline how they’re diagnosed and treated.

What is an anal fissure?

An anal fissure is a small tear or an open sore (ulcer) in the thin, moist tissue (mucosa) which lines the large intestine near the anus. It can cause pain and bleeding, which is usually bright red, during and after bowel movements (poos).

Anal fissures are very common and aren’t usually serious. They can affect people of all ages. But children and young adults between 10 and 30 years of age are more likely to get them.

Anal fissure symptoms

The signs and symptoms of an anal fissure may include:

  • Pain, sometimes quite sharp, during bowel movements

  • A burning or stinging pain after bowel movements that can last for a few hours

  • Bright red blood in the stool or on the toilet paper after a bowel movement

  • A visible tear in the skin around your anus

  • A small lump or skin tag on the skin near the anal fissure

What causes anal fissures?

Anal fissures are usually caused by constipation when hard or large poos tear the lining of the anal passage.

Other anal fissure causes include:

  • Chronic diarrhoea

  • Pregnancy and childbirth

  • Inflammatory bowel disease (IBD), like Crohn’s disease or ulcerative colitis

  • A sexually transmitted infection (STI), like syphilis or herpes

  • Having unusually tight anal sphincter muscles

  • Anal intercourse

How is an anal fissure diagnosed?

The doctor will ask you about the symptoms you’ve been experiencing. They may also ask you some questions about your bowel movements.

A physical examination will usually follow which involves the doctor making a gentle inspection of the anal area. Often, if you have an anal fissure, the doctor will quickly see the tear.

Occasionally, a GP may decide to do a digital rectal examination. This involves inserting a gloved finger covered in lubrication into the anus to feel any lumps or abnormalities.

The doctor may refer you to a specialist if they think you have a condition causing the anal fissure.

Tests a specialist may use include:

  • Anoscopy – a small, rigid tube called an anoscope is inserted into the anus to look at the lining of the anus and rectum

  • Flexible sigmoidoscopy – a thin, flexible tube with a tiny camera is inserted into the anus to examine the lower part of your bowel.

  • Colonoscopy – a long, thin, flexible tube with a tiny camera inside it is passed into your bottom. You’ll be given a laxative to empty your bowels before the procedure

Treatment for an anal fissure

Anal fissures usually heal themselves within a few weeks. But they can come back if they’re caused by constipation that’s left untreated.

Anal fissure treatment may include:

  • Laxatives – to help keep your bowel movements soft so that you can poo more easily

  • Pain-killing medication – medicines like paracetamol or ibuprofen if you have a burning or stinging pain after bowel movements

  • Glyceryl trinitrate (GTN) – if symptoms persist, a doctor may prescribe an anal fissure cream. This is an ointment that’s applied to the anal canal (rectum area) to expand the blood vessels in and around the anus, so that your anal fissure heals quicker

  • Surgery – may be recommended if you have chronic (long-term) anal fissures. The procedure, called a lateral internal sphincterotomy (LIS), involves cutting a small part of the anal sphincter muscle to reduce spasms and pain. It is a very effective treatment option, although there is a small risk of bowel incontinence (loss of bowel control)

Easing the symptoms of an anal fissure

There are some simple things you can do at home to help relieve your discomfort, promote healing and prevent further anal fissures from developing:

  • Make sure you’re eating plenty of fibre. Foods rich in fibre include fruits, vegetables, whole grains and nuts. Adults should aim to eat about 25 to 30 grams of fibre a day

  • Drink plenty of fluids to prevent constipation

  • Exercise regularly

  • Avoid straining too hard during bowel movements. This causes pressure which can open an anal fissure that’s healing or cause a new tear

  • Don’t ignore the urge to poo – this can cause the poo to dry out and harden, making it harder to pass

  • Take paracetamol or ibuprofen to relieve any pain you’re experiencing. A warm bath can soothe your discomfort

Last updated:
Reviewed by:
Dr Rhianna McClymont, Lead GP at Livi