Display Patient Information Leaflets

Anal Fissure

Posted Tuesday, 31 December 2024

Date issued: December 2024

For review: December 2026

Ref: C-607/AC/Colorectal/Anal Fissure

What is an anal fissure?

An anal fissure is a small tear in the skin lining the back passage (anus). Although the tear is very small, it can be very painful as the skin in the anal canal is very sensitive. Fissures can occur in adults and children. It can be a ‘one off’ problem, caused by constipation or diarrhoea. The pain can be sharp when you open your bowels and may last up to several hours after you have had a poo. You may also notice some bleeding on the tissue paper when wiping, or in the toilet bowl. Some people may experience some itching and discharge.

Fissures can come and go, usually lasting 1 or 2 weeks. If it lasts for more than 6 weeks, it is called ‘chronic’ fissure, chronic means persistent. In a small number of people, fissures may also develop due to other reasons such as anal sex, infections or other health factors. Further investigations are carried out to establish the cause of a chronic fissure.

When the fissure heals, some people may notice a small harmless skin tag, called a sentinel pile, at the entrance of the anal canal.

What causes an anal fissure?

The most common cause is passing a hard poo, which can tear the delicate skin just inside the anus, leaving a small cut, similar to a ‘paper cut’. This may bleed when having a poo. The other likely cause of a fissure is tightening of the anus (spasms), which some people have due to increased muscle tone (sphincter) in the anus. This is likely to cause chronic fissures. The muscle spasm can cause extreme discomfort while going to the toilet and for some time afterwards. This often puts people off going for a poo, but ignoring this urge will cause the poo to get harder and make the problem worse.

Emptying the bowels while the poo is hard may open the wound again and delay the healing process.

What treatments are available?

It is important to treat your problem of hard poo and/or constipation first. A diet that is high in fibre and fluids is essential to naturally soften and bulk the poo, making them easier to pass comfortably.

How do I avoid constipation?

Simple changes in your lifestyle and diet can help prevent constipation:

Increase your fibre and fluid. Drink at least 15 cups (2 litres) of fluid a day. If the stool is small and hard this will help to bulk up and soften it.
Do not strain to pass a stool as this will damage the lining of the anus. Avoid sitting on the toilet for too long and limit the time to 5 minutes.
Avoid putting off going to the toilet as this will make you more constipated.
Do some regular exercise as this will help with having regular bowel movements and reducing the risk of constipation.
Discuss your medication with your GP or pharmacist as some may cause constipation.

If stools are soft and frequent, more fibre can also help reduce frequency by thickening the poo.

What is dietary fibre?

Dietary fibre is a type of carbohydrate in our foods. It adds bulk to the poo and helps food pass through the gut. Try to introduce the following foods into your diet to increase the fibre content:

Fresh fruit and vegetables, particularly if skins are eaten. Aim for 5 portions per day.
Wholegrain bread or rolls (such as granary or wholemeal).
Wholemeal pasta.
Brown rice.
Wholegrain breakfast cereals, including porridge, Weetabix®, Shredded Wheat®, muesli or Branflakes®.
Wholemeal or oatmeal crackers and biscuits.
Nuts, dried fruits and seeds.
Baked beans and other beans such as kidney or butter.
Chickpeas and lentils.

Fibre works by absorbing many times its own weight in water. This makes your poo softer and easier to pass. It is very important to increase your fluid intake when increasing your fibre intake. It is sensible to gradually introduce high fibre foods and not to suddenly change your diet.

Fibre supplements

You may be advised to take a fibre supplement. You can buy this over the counter at your local pharmacy without a prescription. For further information about this medicine please refer to the patient information leaflet inside the pack. You may also be prescribed stool softeners to keep your poo soft. Please follow the instructions that come with the medication.

Hygiene

Poo contains natural chemicals that irritate the skin around the back passage. Where possible, wash the area carefully after you go to the toilet and pat dry. Do not use soap as it may irritate the skin. Alcohol-free moist toilet tissues will be more comfortable than toilet paper. Antiseptics, talc are not recommended. Wear cotton underwear and avoid tight-fitting underwear to allow the skin to breath.

Warm bath or Sitz bath

A 15-minute bath in warm water can also soothe and help ease the pain. You can also purchase a sitz bath. This is a shallow bowl you can place over the toilet. You can then sit in some warm water to help soothe the area.

Anal Intercourse

With an anal fissure it would be recommended that you refrain from anal intercourse or inserting anything into the anus, as its likely to over stretch the tissue and prevent it from healing.

Is there any treatment to stop anal muscle spasm?

Most fissures heal by themselves or with dietary changes. However, if you have increased muscle tone in the anus you may be prescribed Glycerine Trinitrate (GTN) 0.4% rectal ointment (Rectogesic®). This will relax the muscle around the anus and increase the blood flow to the fissure and help it heal quicker .

How do I use the GTN 4mg/g rectal ointment?

If you apply Glyceryl Trinitrate (GTN) ointment to the anus, it relaxes the muscle around the anus (the anal sphincter) and increase the blood flow. This allows the fissure to heal better. It may also ease the pain very quickly.

About 7 in 10 people with a chronic anal fissure are cured with a course of GTN ointment. (About 5 in 10 will heal in this time with the ‘traditional’ treatment of regular warm baths and using an anaesthetic cream for pain relief.) Therefore, the chance of cure by using GTN is better than the traditional method.

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 tissue. 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 onto a finger (which you can cover beforehand with cling film, disposable glove or a finger cot). You then place the ointment just inside the anus. Wash your hands following as the medication is absorbed through the skin.
The ointment is used every 12 hours 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 what side-effects that may occur.
Up to 6 in 10 people have a headache after applying GTN ointment as the GTN gets into the bloodstream. The headache usually goes within 30 minutes. 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. If you already take painkillers, speak to your pharmacist before starting any new painkiller so that they can decide if it is suitable for you to take with your existing medication.
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 (but may not be as effective as using the full dose inserted into the anus).

Possible side effects of GTN ointment

For people who develop bad side-effects such as headache, your doctor/nurse may advise an alternative medication.
Itching or burning of the anal canal.
Anal bleeding.
Allergic skin reactions.
Fainting on standing, dizziness, light-headiness, blurred vision and tiredness.
Fast heartbeat or palpitations.
Nausea or vomiting

Is there other medicine I can use?

Diltiazem 2% is another rectal cream; it is only available on a prescription and may be used if the GTN rectal ointment isn’t suitable for you. It also relaxes the anal spasms and increases the blood supply to the fissure to help it heal quicker. It can cause skin itching which usually disappears after a few days.

Painkillers

If you have prolonged burning pain after having a poo, you can usually have common painkillers such as paracetamol or ibuprofen. Please check with your local pharmacist as to whether you can have. Please make sure you follow the dosage instruction and the patient information leaflet. ®

Local anaesthetic

Sometimes it is appropriate to prescribe a local anaesthetic to numb the area before you have a poo. A topical medicine is one which you rub directly into the area, it will not help the fissure to heal, but it can help to ease the pain for you.

Lidocaine is commonly prescribed topical anaesthetic for anal fissures and is commonly used just for a few days.

Do I need any other investigations?

It may be necessary for you to have some blood tests to see if there is any infection or signs of inflammation. A colonoscopy or flexible sigmoidoscopy may be organised which a ‘camera’ to look inside the bowel. We may organise for you to have some investigations to assess the sphincter strength. These tests are called anal manometry. These are important as it helps the Consultant to decide what other options are suitable for you.

You may be referred to SHIP (Sexual health in Plymouth) if we think that you may have a sexually transmitted infection, which would be discussed with you at your appointment.

Other options

If standard treatment does not work, you may be offered a Botox injection. The drug is injected under general anaesthetic into the anal sphincter muscle to relax the spasms. This is done as a day case.

The other main surgical option is called lateral sphincterotomy, whereby a small cut is made in the inner muscle around the anus. This reduces the muscle spasms and increases the blood supply to help the fissure heal. If this treatment is recommended, then your hospital doctor will explain the risks and benefits in detail so that you are well informed before agreeing to this procedure.

A small number of patients with fissures may need another procedure called a ‘flap’ to try to get the fissure to heal, particularly after repeated conservative measures and botox injections.

If you previously had an untreated anal fissure, it is highly likely that this will return in the future. The best way to stop this is to read our advice in the How do I avoid constipation? section.

Prevention

Some people seem prone to recurring anal fissures. Up to 3 in 10 people who are successfully treated with GTN ointment will have one or more recurrences at some time in the future. It is thought that these people have an ongoing higher than average pressure (tone) of the muscle around the anus. They are more likely to tear the rim of the anus if it is stretched, (so, avoiding constipation is important.) 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 recurrence.