Anal Fissure

An anal tear (fissure) causes pain around the back passage (anus). The pain is worse when you pass stools (faeces). A fissure heals within 1-2 weeks in most people, but lasts longer in some. Treatment aims to ease the pain until the fissure heals, and to keep the faeces soft and easy to pass. An anal fissure that lasts more than six weeks is called a chronic anal fissure. Treatment options for a chronic anal fissure include an ointment to relax the anal muscle, and surgery.

An anal fissure is a small tear of the skin around the back passage (anus). Although the tear of an anal fissure is usually small (usually less than a centimetre), it can be very painful. This is because the anus is very sensitive. The pain tends to be worse when you pass stools (faeces) and for an hour or so after passing faeces. Often an anal fissure will bleed a little. You may notice blood after you pass faeces. The blood is usually bright red, and a small amount may be seen on the toilet paper or coating your faeces.

Anal fissures are common, both in adults and in children. They are not usually serious, but they are sore and can be distressing, particularly for children.

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 (chronic means persistent). This is uncommon, but treatment can still be effective.

Stretching and tearing of the rim of the back passage (anus) can occur when a person passes particularly hard stools (faeces). In most people, this skin damage will heal quickly with no problems. But some people seem to have a higher than normal tone (pressure) of the muscle around the anus (the anal sphincter). The muscle is 'tighter' than usual. It is thought that this increased tone may reduce the blood supply to the anus and so slow down the skin healing process. This can cause an anal tear (fissure) to develop. Once a fissure has developed, pain when passing faeces can increase the anal tone further. This makes pain and symptoms worse and a vicious cycle can be set up.

Constipation can make an anal fissure more likely to develop. In about 1 in 10 cases, the fissure occurs during childbirth. Sometimes an anal fissure occurs if you have bad diarrhoea.

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. In these situations you will have other symptoms and problems as well. These type of fissures are not dealt with further in this leaflet.

Your doctor will usually diagnose an anal tear (fissure) by your typical symptoms and by examining the skin around your back passage (anus).

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In most people the tear (fissure) heals within a week or so, just like any other small cut or tear to the skin. Treatment aims to ease the pain and to keep the stools (faeces) soft whilst the fissure heals.

Easing pain and discomfort

  • Warm baths are soothing, and may help the back passage (anus) to relax which may ease the pain.
  • A cream or ointment that contains an anaesthetic such as lidocaine may help to ease the pain. You should only use this for short periods (up to 5-7 days). If you use it for longer, the anaesthetic may irritate or sensitise the skin around the anus. You can get one of these creams or ointments on prescription. You can also buy some of these products at pharmacies, without a prescription.The cream/ointment should be applied before going to the toilet.
  • A cream or ointment that contains steroid medication may be prescribed by a doctor if there is a lot of swelling (inflammation) around the fissure. Steroids reduce inflammation, and may help to reduce any swelling around a fissure. This may help to ease any itch and pain. You should not use it for longer than one week at a time.
  • 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 cause irritation.
  • Painkillers such as paracetamol or ibuprofen may help to ease the pain (but avoid codeine - see below).

Avoid constipation and keep the faeces soft

  • Eat plenty of fibre which is found in fruit, vegetables, cereals, wholemeal bread, etc.
  • Have lots to drink. Adults should aim to drink at least two litres (10-12 cups) of fluid per day. You will pass much of the fluid as urine. However, some is passed out in the gut and softens the faeces. Most sorts of drink will do, but alcoholic drinks can be dehydrating and may not be so good.
  • Fibre supplements and laxatives. If a high-fibre diet is not helping, you can take fibre supplements (bulking agents) such as ispaghula, methylcellulose, bran or sterculia. Methylcellulose also helps to soften faeces directly which makes them easier to pass. You can buy these at pharmacies or get them on prescription. A laxative such as lactulose or a macrogol laxative may sometimes be suggested. 
  • Toileting. Don't ignore the feeling of needing 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.
  • Avoid painkillers that contain codeine such as co-codamol, as they are a common cause of constipation. Paracetamol is preferable to ease the discomfort of a fissure.

There are separate leaflets called Constipation in Adults, Constipation in Children and Fibre and Fibre Supplements that provide more details about fibre and constipation.

Anal fissures in children

The above measures apply to children who have a fissure as much as to adults. In children, the pain often makes them hold on to their faeces. This may lead to a vicious circle, as then even larger and harder faeces form. These then cause more pain when they are finally passed. Therefore, in addition to the above measures, a short course of laxatives may be prescribed for children with an anal fissure. The aim is to make sure their faeces are soft and loose whilst the fissure heals.

An anal tear (fissure) will usually heal within 1-2 weeks in most people. However, it can take longer to heal in others. Even if it has lasted six weeks, technically becoming known as chronic anal fissure, there is still a reasonable chance that it will heal on its own without treatment. However, treatment can help to heal the fissure as quickly as possible.

Treatment aims to:

  • Relax the tone of the muscle around the back passage (anus). This allows a good blood flow and enables the fissure to heal as quickly as possible.
  • Keep the stools (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). It also increases the blood supply to the damaged skin by dilating the blood vessels in that area. This may allow the fissure to heal better. It may also ease the pain. A doctor may advise that you use GTN ointment if you have had an anal fissure for longer than a week or so, and particularly if you have a persistent (chronic) anal fissure.

GTN ointment may help in some, but not all, cases. Research studies have shown that, for people with a chronic anal fissure, about 6 in 10 fissures healed with GTN treatment. This compared to about 5 in 10 that healed with no treatment. So, the effect of GTN ointment is modest, but may well be worth a try.

Some points to note if you use GTN ointment include the following:

  • There is only one branded product of GTN ointment that is used to treat anal fissure. It is called Rectogesic® and is only available on prescription. Rectogesic® contains 0.4% GTN. You should use this exactly as described on the leaflet that comes with the packet. For example:
    • 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. (Some doctors advise to continue with the ointment for a full 6-8 weeks even if the pain goes much sooner. This is because it often takes 6-8 weeks of treatment for the fissure to heal fully, even if the pain has gone.)
    • The product leaflet gives details of who should not use the ointment and of side-effects that may occur. For example, it should not normally be used by children unless prescribed by a specialist and it may not always be advised in pregnant women.
  • About 5 in 10 people have a headache after applying GTN ointment. (The GTN gets into the bloodstream and may cause a headache.) The headache usually goes within 30 minutes or so. Painkillers such as paracetamol will help if a headache occurs. If headaches are troublesome, try using a smaller amount of ointment for a few days, and then gradually increase the amount back to normal over several days.
  • Another tip if you get bad headaches is to rub a smaller amount of ointment (a pea-sized amount) around the rim of your anus rather than inserting the full amount into the anus. GTN is absorbed more into the bloodstream from the thin skin inside the anus. Using a smaller dose of ointment just on the rim of the anus may avoid side-effects. (However, it may not be as effective as using the full dose inserted into the anus.)
  • Occasionally, GTN ointment can cause dizziness and light-headedness because it can cause a drop in blood pressure. To try to avoid this, get up slowly after you have been lying or sitting down and avoid drinking too much alcohol. 

Other medicines

Some studies have shown that other medicines may also help to relax the anal sphincter muscle and increase the blood supply to the area, so helping healing of an anal fissure. For example, medicines called calcium-channel blockers, such as diltiazem. These medicines do not seem to be any more effective than GTN ointment. They may sometimes be suggested for people unable to use GTN ointment.

An injection of botulinum toxin into the anal sphincter muscle has also been shown to relax the anal sphincter muscle and so help anal fissures to heal. This treatment may be suggested in certain cases - for example, if other treatments have not been successful.

Surgery

An operation is an option if the fissure fails to heal despite the above treatments. It is also an option if you have fissures which happen again (recur). 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 day case surgery (you will not usually have to stay overnight in the hospital).

The success rate with surgery is very high - at least 9 in 10 cases are cured.

As with any operation, there is a risk of complications. After this operation, some people have poor control of wind (gas). A very small number have soiling of underclothes, or mild bowel incontinence. But, studies have demonstrated that the risk of these complications is small. The vast majority of people who have this operation are pleased with the result to be free from the symptoms of an anal fissure. And for some, to be free of the problem of recurring anal fissure.

Some people seem prone to anal tears (fissures) happening again (recurring). Up to half of people who have a persistent (chronic) anal fissure successfully treated with GTN ointment will have one or more recurrences at some future time. It is thought that these people have an ongoing higher-than-average pressure (tone) of the muscle around the back passage (anus). They are more likely to tear the rim of the anus if it is stretched. However, a further course of GTN ointment can be used to help to heal any future fissure. Surgery may be an option if you have frequent recurrences.

If you have had one anal tear (fissure), after it has healed you have a higher-than-average chance of having another one at some future time. The best way to avoid a further fissure is not to become constipated by using the measures described above. That is, a high-fibre diet, fluid, etc. Leaflets that list foods high in fibre are commonly available. Ask your practice nurse for one if needed.

Original Author:
Dr Tim Kenny
Current Version:
Peer Reviewer:
Dr John Cox
Last Checked:
12/03/2014
Document ID:
4192 (v40)
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