An anal fissure is a tear or ulcer (open sore) that develops in the lining of the anal canal.

The anal canal is the last part of your large intestine, located between your rectum (where stools are stored) and the opening in your bottom through which you pass stools.

Signs and symptoms

The most common symptoms of anal fissures are:

  • a sharp pain when you pass stools (faeces), often followed by a deep burning pain that may last several hours
  • bleeding when you pass stools  most people notice a small amount of bright red blood either in their stools or on the toilet paper

When to see your GP

Visit your GP if you think you have an anal fissure.

Don't let embarrassment stop you seeking help. Anal fissures are a common problem that GPs are used to dealing with.

Most anal fissures get better without treatment, but your GP will want to rule out other conditions with similar symptoms, such as haemorrhoids (swellings in or around the rectum and anus). They can also advise you about self-help measures and treatments that can help relieve your symptoms and reduce the risk of fissures recurring.

Diagnosing anal fissures

Your GP will first ask about your symptoms and the type of pain you have been experiencing. They may also ask about your toilet habits.

Your GP will usually be able to see the fissure by gently parting your buttocks.

digital rectal examination (where your GP inserts a lubricated, gloved finger into your anus to feel for abnormalities) is not normally used to diagnose anal fissures, because it is likely to be painful.

Your GP may refer you to a specialist for assessment if they think something serious may be causing your fissure. This may include a more thorough examination of your anus, carried out using anaesthetic to minimise pain. 

The measurement of a person's anal sphincter (the ring of muscles that open and close the anus) pressure is occasionally used for fissures that have not responded to simple treatments.

What causes anal fissures?

Anal fissures are most commonly caused by damage to the lining of the anus or anal canal. Most cases occur in people who have constipation, when a particularly hard or large stool tears the lining of the anal canal.

Other possible causes of anal fissures include:

In many cases, no clear cause can be identified.

Who is affected

Anal fissures are relatively common, with an estimated 1 in every 10 people affected at some point in their life.

Anal fissures affect both sexes equally and occur in people of all ages, including very young children. However, most cases occur in children and young adults between the ages of 10 and 30.

Treating and preventing anal fissures

Anal fissures usually heal within a few weeks without the need for medical treatment, although they can easily recur if they are caused by constipation and this remains untreated. In some people, symptoms from anal fissures last six weeks or more (chronic anal fissures).

It can be helpful to adopt some simple self-help measures to help make it easier to pass stools, which can allow existing fissures to heal and reduce your chances of developing fissures in the future. These measures include:

  • making sure you have plenty of fibre in your diet
  • staying well hydrated by drinking plenty of fluids
  • not ignoring the urge to pass stools
  • exercising regularly

You can help soothe the pain by taking simple painkillers, such as paracetamol or ibuprofen, or by soaking your bottom in a warm bath several times a day (particularly after a bowel movement).

Your GP can also prescribe medication to help relieve your symptoms and help speed up the healing process. This can include laxatives to help you pass stools more easily and painkilling ointment that you apply directly to your anus.

In persistent cases where self-help measures and medication have not helped, surgery may be recommended. Surgery is often very effective in treating anal fissures, but it does carry a small risk of complications, such as temporary or permanent loss of bowel control (bowel incontinence).

Read more about treating anal fissures and preventing anal fissures.

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Page last reviewed: 06/05/2014

Next review due: 06/05/2016