Anal Fissure

anal fissure What is an anal fissure?

An anal fissure is a small tear of the skin of the anus. The pain tends to be worse when you pass feces (sometimes called stools or motions) and for an hour or so after passing feces. Often an anal fissure will bleed a little. You may notice blood after you pass feces.

In most people the fissure heals within 1-2 weeks or so, just like any other small cut of the skin. Some fissures take longer to heal. A fissure that lasts more than six weeks is called a chronic anal fissure.

Causes of an anal fissure?

Common causes

Most anal fissures are thought to be due to passing large or hard feces when you are constipated. The rim of the anus may stretch and tear slightly. Spasm (tightening) of the muscle around the anus (the sphincter) may play a part in causing the tear, or in slowing down the healing process.

Anal fissures and other conditions

In a minority of cases, a fissure occurs as part of another condition. For example, as a complication of Crohn's disease or an anal herpes infection.

What is the initial treatment for an anal fissure?

In most people the fissure heals within a week. Treatment aims to ease the pain and to keep the feces soft whilst the fissure heals.

  • Easing pain and discomfort
  • Warm baths are soothing, and may help the anus to relax which may ease the pain.
  • A cream or ointment that contains an anaesthetic may help to ease the pain.
  • A cream or ointment that contains a steroid may be prescribed by a doctor if there is a lot of inflammation around the fissure.
  • Wash the anus carefully with water after you go to the toilet. Dry gently. Don't use soap whilst it is sore as it may irritate.
  • Painkillers such as paracetamol or ibuprofen may help to ease the pain.
  • Avoid constipation and keep the faeces soft
  • Eat plenty of fibre which is in fruit, vegetables, cereals, wholemeal bread, etc.
  • Have lots to drink.
  • Don't ignore the feeling of needing the toilet to pass faeces. Some people suppress this feeling and put off going to the toilet until later. This may result in bigger and harder faeces forming that are more difficult to pass later.
  • Anal fissures in children

    The above measures apply to children as well as adults. In children, the pain often makes them hold on to their feces. Therefore, in addition to the above measures, a short course of laxatives may be prescribed for children with an anal fissure.

    What if the anal fissure does not heal with the above measures?

    This requires slight alteration in the treatment strategy:

    • Relax the tone of the muscle around the anus. This allows a good blood flow and enables the fissure to heal as quickly as possible.
    • Keep the faeces soft and easy to pass.
    • Glyceryl trinitrate ointment

    If you apply glyceryl trinitrate (GTN) ointment to the anus, it relaxes the muscle around the anus (the anal sphincter). This may allow the fissure to heal better. It may also ease the pain very quickly.

    A standard dose is 2.5 cm squeezed out of the tube. (A measuring line comes with the product to measure 2.5 cm of ointment.)

    You squeeze a dose of ointment on to a finger (which you can cover beforehand with cling film or similar). You then place the ointment just inside the anus.

    The ointment is used every 12 hours until pain goes, or for up to 8 weeks maximum.


    An operation is an option if the fissure fails to heal despite the above treatments. It is also an option if you have recurring fissures. The usual operation is to make a small cut in the muscle around the anus (internal sphincterotomy). This permanently reduces the tone (pressure) around the anus and allows the fissure to heal. This is a minor operation which is usually done as a day case under general anaesthetic. The success rate with surgery is very high - at least 9 in 10 cases are cured.

    Will it recur?

    Some people seem prone to recurring anal fissures. It is thought that these people have an ongoing higher than average pressure (tone) of the muscle around the anus.

    Prevention of a further anal fissure

    If you have had one anal fissure, after it has healed you have a higher than average chance of having another one at some time in the future. The best way to avoid a further fissure is not to become constipated.

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