Anal fissure

What is an anal fissure?

An anal fissure is a small tear or open sore (ulcer) in the skin just inside your anus (bottom or back passage). It causes pain and sometimes bleeding when you have a bowel movement (poo). Anal fissures are common and often go away by themselves. But if they don’t, there are treatments that can help.

Causes of anal fissure

The cause of anal fissure is often unknown, or you might be aware of certain factors that have caused it.

What is the main cause of anal fissure?

It’s often thought to be caused by hard or painful bowel movements. These can cause the muscles around your anus to tense up and spasm, making your anus more likely to tear. It also reduces the blood supply to the area, which makes it harder for any tears to heal.

Sometimes, there is a clear underlying cause for an anal fissure. These can include:

• constipation – a hard poo can cause a tear
• pregnancy or giving birth – this can put pressure on the area between the anus and vulva (your perineum)
• inflammatory bowel disease such as Crohn’s disease
• a sexually transmitted infection or a skin infection
• a skin condition such as psoriasis
• medicines that are constipating such as opioid painkillers or some chemotherapy drugs
• trauma to your anus – for example, through having anal sex or through surgery
• bowel cancer

Symptoms of anal fissure

If you have an anal fissure, you’re likely to experience symptoms that can be worse after a bowel movement.

What does an anal fissure feel like?

With an anal fissure, you may feel a tearing sensation when you poo.

Once you have a tear in your anus, it can cause:

• pain when you poo - this may be sharp, searing, or burning pain in or around your bottom
• a deep, burning pain for several hours after you poo
• bleeding from your anus – you might see blood in the toilet or on the toilet paper after you’ve had a poo
• spasms (sudden tightening) in the muscles around your anus when you poo

These symptoms may not always be due to an anal fissure. Other conditions, like piles (haemorrhoids) can cause similar symptoms. If you have any of the symptoms above, contact a GP for advice. You should always seek medical advice if you notice bleeding from your bottom.

Diagnosis of anal fissure

A GP will usually be able to diagnose an anal fissure by asking about your symptoms and examining you.

A doctor may:

• examine you by asking you to lie on your side with your knees bent towards your chest
• gently part your buttocks to examine the area and see if there’s a fissure

If there’s uncertainty about what’s causing your symptoms or if initial treatments don’t help, your GP may refer you to a colorectal surgeon. This is a surgeon who specialises in conditions affecting your bowel and back passage.

Self-help

There are certain things you can do to ease your symptoms and help your anal fissure to heal.

How do you know if an anal fissure is healing?

Most anal fissures heal by themselves within six to eight weeks.

As your fissure is healing, your pain should lessen, and any bleeding should stop. You should have a follow-up appointment with your doctor after six to eight weeks, to check that the fissure has healed.

How do you heal an anal fissure?

Your anal fissure should heal by itself, but the following tips may help.

Eating and drinking

Gradually increase the fibre in your diet as this will help keep your poo soft and easier to pass. You should aim for up to 30g per day in total. You can get fibre from wholegrain foods, fruit, and vegetables. You should also make sure you’re drinking enough fluids.

Staying regular

Because of the pain, you may tend to delay going for a poo. But make sure you go to the toilet as soon as you feel the need and try not to strain when you go, as this can make the fissure worse.

Hygiene and comfort

Keeping the area clean and dry is important to help with healing and prevent infection. Sitting in a warm bath after you’ve had a bowel movement may help to relieve any pain.

You can also manage pain with over-the-counter painkillers such as paracetamol or ibuprofen. Make sure you read the patient information leaflet in the packet.

Treatment of anal fissure

If your pain is severe or your symptoms aren’t improving, there are a number of treatments your doctor may suggest.

Medicines

There are several different types of medicine that can help to relieve pain or help the fissure to heal.

Laxatives or stool softeners

Ispaghula husk or lactulose can help if you’re constipated. These work by softening your poo and making it easier to pass. You can buy laxatives over the counter from a pharmacy. A doctor will need to prescribe them if they are for a child.

Anaesthetic ointment

Your GP may prescribe an anaesthetic ointment (for example, lidocaine) to help with pain when you poo. You apply this ointment to your anus to help numb the area before you have a bowel movement.

Glyceryl trinitrate (GTN) ointment

Your doctor may also suggest an ointment containing glyceryl trinitrate (GTN). This helps to relax the muscles in your anus and improve blood flow to the area, which helps the fissure to heal. You’ll need to keep using it for six to eight weeks.

GTN ointment isn’t suitable for children or pregnant women.

Calcium-channel blockers

A cream containing calcium-channel blockers (for example, diltiazem cream) also relaxes the muscles and improves blood flow to the area. It has fewer side-effects than GTN ointment.

Procedures to treat anal fissure

If other treatment options haven’t helped your anal fissure to heal or it keeps coming back, your GP may refer you to a colorectal surgeon. Your surgeon may discuss other options with you. These include the following.

• Botox injections into the sphincter muscle in your bottom. The aim is to temporarily relax this muscle so that your fissure can heal.
• Lateral internal sphincterotomy – a type of surgery that involves cutting the sphincter muscles in your anus. This releases the tension around your anus and lets your fissure heal.
• Fissurectomy – cutting away the damaged skin around your anal fissure.
• Anal advancement flaps – taking healthy skin from your anal lining and using it to replace the broken skin in your fissure.

There is more information about these procedures in our page of information on anal fissure procedures.

Prevention of anal fissure

You can reduce your risk of developing an anal fissure by preventing constipation.

A healthy balanced diet that contains plenty of fibre can help. It’s also important to make sure you’re 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 tell you the best way to manage your condition and reduce your risk.