Anal fissure

Expert reviewer, Mr Simon M Phillips, Consultant Colorectal Surgeon.
Next review due August 2018.

An anal fissure is a small tear or ulcer (open sore) in your skin around the opening of your bottom. It can be very painful and sometimes bleed, usually after you go to the toilet (to pass faeces). About one in 10 people get an anal fissure at some point in their life.

An image showing an anal fissure

About anal fissure

Your anus is the area at the very end of your bowel. Anal fissures usually develop at the part of your anus towards your back – in line with the cleft of your buttocks. You can sometimes get one at the front of your anus, or even both together.

An anal fissure will usually heal within six weeks, and it’s called an acute anal fissure. If it lasts for longer than six weeks, it’s known as a chronic anal fissure.

You can get an anal fissure at any age, but it’s most common in people aged 15 to 40. 

Symptoms of anal fissure

If you have an anal fissure, you may have the following symptoms.

  • A sharp, searing or burning pain in, or around, your bottom, which can last for a couple of hours after you go to the toilet. Some people describe the pain of an anal fissure as like passing broken glass.
  • Spasms in your anus.
  • Bleeding. After you go to the toilet, you might see blood on the toilet paper or drops of blood in the toilet bowl.
  • A sentinel pile. This is a tag of skin that can develop on the edge of your anus below the fissure. This can develop after you get the fissure.

These symptoms may be caused by something other than an anal fissure. One condition they’re often confused with is piles (haemorrhoids), for example. If you have any of these symptoms, contact your GP.

Diagnosis of anal fissure

Your GP will ask about your symptoms and your medical history. They may examine the area too. They’ll ask you to lie on your side with your knees bent towards your chest and part your buttocks to do this. They’ll be able to see if there’s a fissure.

If your symptoms haven’t improved with treatments (described below) after about six to eight weeks, your GP may refer you to see a colorectal surgeon. This is a surgeon who specialises in bowel conditions. At the hospital, they’ll examine your bottom carefully and suggest a plan for treatment.

You may also need to have some other tests to rule out other bowel problems, such as a proctoscope test. This involves using a narrow tube to look at the inside of your rectum and large bowel. Or you might have an ultrasound scan. This uses sound waves to produce an image of the inside of your anus.


To help an anal fissure heal, it’s important to keep your faeces soft when you go to the toilet. This will help to stop you stretching your anus, and with the pain caused by the fissure.

If you make some changes to your diet and lifestyle, it can help prevent constipation and make your faeces softer, and therefore easier to pass. You can do this by:

  • eating a healthy balanced diet with lots of fibre
  • taking a fibre supplement (bulk-forming laxative), such as sterculia (Normacol) or ispaghula husk (Fybogel)
  • drinking enough fluids so you don’t become dehydrated
  • doing regular exercise

It may help to sit in a warm bath (10–15 minutes) after you go to the toilet to relieve any discomfort.

Treatment of anal fissure

Sometimes an anal fissure will heal within a week or two without any treatment. An anal fissure often heals if you make some changes to your diet and take medicines, or use creams. If it doesn’t get better, you may need to have surgery.


Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your doctor or pharmacist for advice.

Medicines to prevent constipation

Your GP may prescribe you a laxative, such as lactulose syrup, to soften your faeces. You can buy laxatives over the counter from a pharmacist without a prescription too. But, it’s important to talk to a pharmacist or your GP before you try laxatives because there are different types that work in different ways.

>Medicines for pain relief

If you need pain relief, you can take over-the-counter painkillers such as paracetamol or ibuprofen. If these don’t help, have a chat with your pharmacist about other options.

Medicines to relieve anal spasm

The opening and closing of your anus is controlled by your internal (inside) and external (outside) anal sphincter muscles. These muscles surround your anus and relax and contract to control your bowel movements when you go to the toilet. You can voluntarily control your external anal sphincter yourself, but not your internal anal sphincter. If you have an anal fissure, your internal anal sphincter often goes into spasm (tenses). This reduces the blood supply to your fissure and prevents it healing.

Your GP may prescribe you the following medicines to relieve the spasm of an anal fissure. It’s important to take these for the full time your doctor recommends to get the best results.

  • Local anaesthetic (eg, lidocaine). This ointment will block pain from your bottom.
  • Glyceryl trinitrate (GTN). This is an ointment that helps the internal sphincter muscle to relax. It reduces the spasm and improves blood flow to your bottom to help the fissure heal.
  • Calcium-channel blockers (eg, diltiazem cream). These medicines work by relaxing part of the sphincter to reduce the spasm and pressure in your anus. Calcium-channel blockers aren’t licensed in the UK to treat anal fissures yet, but your doctor may prescribe one to you ‘off-label’. Doctors can legally prescribe outside the licence if they think the medicine will work for you.

Easing the anal spasm with medicines can help the fissure heal, usually over about six to eight weeks. But your anal fissure might come back. You may need to take them alongside painkillers.

Injections to relieve anal spasm

Botulinum A toxin (eg, Botox) is being used more and more by surgeons to treat anal fissure. In this procedure, your surgeon will inject botulinum A toxin into your internal sphincter muscle to help it relax. If you have a sentinel pile, your surgeon may remove it during the procedure to help the healing process.

The effects of the treatment last around three months, by which time it's hoped the fissure will have healed. Like calcium-channel blockers, the use of botulinum A toxin is off-label.


If treatment with botulinum A toxin doesn’t work, you may need surgery to relax your sphincter muscle or to remove the damaged skin.

There are a number of operations to treat an anal fissure. For more information about what’s involved, see Related information.

Causes of anal fissure

There are lots of reasons why you may get an anal fissure. It’s often caused by a hard or painful bowel movement, which damages the surrounding skin.

Other reasons why you get an anal fissure include:

  • straining when you go to the toilet – sometimes because you’re constipated
  • having diarrhoea
  • inflammatory bowel disease, such as Crohn’s disease
  • having an infection in the skin around your anus, such as a sexually transmitted infection
  • taking certain medicines, such as painkillers that contain opiate
  • trauma – for example, through having anal sex
  • anal cancer
  • giving birth

Prevention of anal fissure

You can reduce your risk of developing an anal fissure by preventing constipation. This is really important if you’ve had an anal fissure in the past. You can prevent constipation by eating a healthy balanced diet that contains plenty of fibre, fruit and vegetables, drinking enough fluids, and exercising regularly.

If you have another health condition that increases your risk of getting an anal fissure, speak to your doctor. They will talk you through how to best manage your condition and reduce your risk of having an anal fissure.

Frequently asked questions

  • It's important to continue to exercise as usual. Exercise helps to increase blood flow, which may help your anal fissure heal.

    Exercise raises your heart rate, which increases blood flow around your body. This may help an anal fissure to heal. Being regularly active also helps to keep food moving through your digestive system, which helps to reduce constipation.

    Remember, keeping physically active is great for your overall health – it can prevent major illnesses such as heart disease, diabetes and bowel cancer. See Related information for tips and advice about keeping fit.

    If your anal fissure is painful when you exercise, see your GP as this may be a sign that you have another condition.

  • A sitz bath is a type of bath – derived from the German word ‘sitzen’ meaning ‘to sit’. You sit in water that only covers your hips and buttocks – a bit like a portable bidet. They’re sometimes used to relieve pain and muscle spasms.

    The warm water may help relieve any discomfort when you go to the toilet. Sitz baths also help to promote good anal hygiene, can decrease anal sphincter spasm and will improve blood flow to your anus. If you use a warm sitz bath for 10–20 minutes after going to the toilet, it may help to relieve the pain from an anal fissure. But there isn’t any scientific evidence to prove that they work yet. 

  • Anal fissures and piles have similar symptoms and causes, but they’re different conditions.

    Both anal fissures and piles can make you bleed after you go to the toilet and can be uncomfortable. But you don’t usually get the same level of pain with piles as you do with an anal fissure. Some people describe the pain of an anal fissure as like passing broken glass.

    Although some of the symptoms are similar, the conditions are quite different. An anal fissure is a small tear or ulcer (open sore) in your skin around the opening of your anus. Whereas piles, also known as haemorrhoids, are swollen veins and muscle around your anus or in your anal canal. Your anal canal is a short, muscular tube with blood vessels. It connects your rectum (back passage) with your anus.

    Both anal fissures and piles can result from straining when going to the toilet. This can happen if you have constipation, so it’s important to eat a healthy diet that contains enough fibre, and to drink plenty of fluids.

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Related information

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  • Reviewed by Rachael Mayfield-Blake, Bupa Health Content Team, July 2016.
    Expert reviewer, Mr Simon M Phillips, Consultant Colorectal Surgeon.
    Next review due August 2018.

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