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Anal fissure

Key points

  • An anal fissure is a small tear in the skin around the opening of your anus.
  • They usually heal within two to four weeks, but can take a lot longer.

An anal fissure is a small tear in the skin around the opening of your anus. It can cause severe pain and sometimes bleeding, usually after a bowel movement.

About anal fissure

Anal fissures are usually found at the part of your anus closest to your back – in line with the cleft of your buttocks. A fissure can also sometimes occur at the front of your anus.

An anal fissure usually heals within two to four weeks. This is known as an acute anal fissure. The term ‘acute’ refers to how long a person has had it, not to how serious the condition is. If it lasts for longer than six weeks, it’s known as a chronic anal fissure.

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

Symptoms of anal fissure

An anal fissure can sometimes be confused with piles (haemorrhoids) because symptoms can be similar. If you have an anal fissure, you may have:

  • a sharp, searing or burning pain in or around your anus, which can last for up to an hour after a bowel movement
  • spasms in your anus
  • a sentinel pile, which is a tag of skin that can develop on the edge of your anus below the fissure

After having a bowel movement, you may notice a streak of blood on the toilet paper or drops of blood in the toilet bowl.

These symptoms may be caused by something other than an anal fissure. But if you have any of these symptoms, see your GP.

Complications of anal fissure

The main complication of an anal fissure is that it may take a while to heal, resulting in a chronic fissure. This can happen if:

  • you have long-term constipation or diarrhoea
  • the tear extends into the ring of muscle that holds your anus closed (this is known as your internal anal sphincter) 
  • pain causes your internal sphincter muscle to spasm, which can increase the pressure within your anus, making it harder to have a bowel movement

The more you strain when having a bowel movement, the less likely it is that the tear will heal.

Causes of anal fissure

There are a number of reasons why you may develop an anal fissure. These include:

  • straining during a bowel movement – often because you’re constipated
  • recurrent or chronic diarrhoea
  • inflammatory bowel disease, such as Crohn’s disease
  • having an infection in the skin around your anus, such as a sexually transmitted infection or HIV
  • being in the third trimester of pregnancy, or childbirth, if you're a woman
  • taking certain medicines – for example, nicorandil (used to treat angina)
  • trauma – for example, through anal intercourse
  • anal cancer
  • chemotherapy or radiotherapy

Diagnosis of anal fissure

Your GP will ask about your symptoms. They may examine the area by parting your buttocks as you lie on your side with your knees bent towards your chest. If your GP can see the fissure, they will discuss your treatment options with you.

If after about six weeks your symptoms haven’t improved with treatment, your GP may refer you to a colorectal surgeon. This is a surgeon who specialises in conditions that affect the bowel. At the hospital, your doctor will do a detailed examination under local anaesthesia. A local anaesthesia blocks pain from your anus and surrounding area, but you will stay awake during the procedure. You may also need to have an ultrasound scan of your anus.

Treatment of anal fissure

To help an anal fissure heal, it’s important not to strain during a bowel movement and manage any pain caused by the fissure. Most anal fissures heal with changes to your diet and the right medicines. However, if the anal fissure doesn’t get better, you may need to have surgery


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

  • eating a 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 that you don’t become dehydrated
  • doing regular exercise

It may help to apply a lubricant, such as petroleum jelly, around your anus before you have a bowel movement. Sitting in a warm bath for 10 to 15 minutes after a bowel movement may also help relieve any discomfort.


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. However, it’s important to see your GP before trying laxatives because there are different types that work in different ways.

If you need pain relief, you can take over-the-counter painkillers such as paracetamol or ibuprofen.

Your GP may prescribe you the following medicines to relieve the spasm of an anal fissure.

  • Local anaesthetic (eg, lidocaine). This may come as a cream, ointment or suppository (a medicine that you insert into your rectum) and will block pain from your anus.
  • Glyceryl trinitrate. This is a rectal ointment that helps the internal sphincter muscle that goes around your anus to relax. It acts to reduce the spasm and improve blood flow to your anus 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 currently licensed in the UK to treat anal fissures but they can be prescribed by doctors for off-label use. This means the medicine is being used to treat a condition that it hasn’t been licensed for. However, doctors can legally prescribe outside the licence if he or she thinks the medicine will be effective for you.

Easing the anal spasm can help the fissure heal over a period of about four to six weeks. However, these treatments may not provide complete relief from your symptoms and you may need to use them with painkillers. Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your doctor or pharmacist for advice.


Botulinum A toxin (eg, Botox) is now being used more and more by surgeons. In this procedure, your surgeon injects botulinum A toxin into the internal sphincter muscle to help it relax. If a sentinel pile is present, your surgeon may remove it during the procedure to help aid healing. 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, your surgeon may suggest that you have a procedure called lateral internal sphincterotomy. During this procedure, your surgeon makes a small cut in the internal sphincter muscle to stop it from going into spasm. This means you will strain less when you go to the toilet and therefore less stress is put on the fissure, giving it time to heal. The procedure is usually done under general anaesthesia, which means you’ll be asleep during the operation.

As with any operation, there are possible complications associated with lateral internal sphincterotomy. Your doctor will talk to you about any that may apply to you so you’re fully informed before you go ahead with the surgery. Speak to your doctor for more information about treatments for anal fissure.

Prevention of anal fissure

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

If you have a condition that increases your risk of having an anal fissure, speak to your doctor. They will discuss with you how to best manage your condition and reduce your risk of having an anal fissure.

Reviewed by Alice Rossiter, Bupa Health Information Team, August 2014.

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For answers to frequently asked questions on this topic, see FAQs.

For sources and links to further information, see Resources.

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  • This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.

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