Anal fissure

Anal fissures are commonly caused by damage to the inner lining of the large intestine or the anal canal. It occurs mostly in people who are constipated, where large or hard poo causes the lining to stretch and tear. Anal sex can cause a similar trauma.

Other causes include inflammatory bowel conditions like Crohn’s disease or ulcerative colitis, sexually transmitted infections such as herpes, or persistent diarrhoea that can irritate and then tear the lining. Fissures can occur during pregnancy or childbirth, but there is not always a clear cause for them.

There are several things you can do at home to prevent constipation. Drinking plenty of fluid, increasing the amount of fibre in your diet and staying active are all important to encourage regular passage of stool.

The pain from a fissure can cause you to avoid toileting but this can worsen the problem. Simple painkillers such as paracetamol or ibuprofen can be bought from your local pharmacy, soaking your bottom in a warm bath with Sitz salts may also be helpful to ease the discomfort.

It may help to apply Vaseline before passing stool, to reduce pain and protect the fissure from further stretch or harmful gut bacteria.

If symptoms persist for more than 1 week, if you are in severe pain or unsure of the diagnosis, or if you are getting repeated fissures, you should book an appointment with your doctor. Similarly, if you have specific concerns about why you've got a fissure, speak to your doctor.

They will ask about your symptoms to try and work out what might have caused your symptoms, and they will ask about any products you’ve tried at home. They will offer to examine your back passage, where they may see the tear.

Haemorrhoids can also cause some pain and anal bleeding, so they may suggest an internal examination, where they insert a gloved finger into your back passage to feel for this or other causes.

You can try simple over-the-counter painkillers such as ibuprofen or paracetamol. Codeine-based medication (opioid medicine) should be avoided as they can cause or worsen constipation.

Symptoms of an anal fissure can be embarrassing for some, but it’s important to remember they are common and your pharmacist or doctor can help, so don’t avoid seeing them if you are bothered by the symptoms and they are not improving with time.

Your doctor can prescribe you laxatives to soften your stool so you can toilet without straining. They may offer stronger painkillers in the form of tablets or creams.

An anaesthetic ointment such as lidocaine 5% can be helpful to use for a few days, to numb the area before passing a stool. Rectal GTN (glyceral trinitrate) 0.4% appointment can help to aid healing, and can be continued for 6 to 8 weeks. It should be avoided in children, pregnancy or breastfeeding.

If your doctor is concerned that something more worrying is causing the fissure, they will refer you to a specialist for review. The specialist will examine you properly using anaesthesia and may use a long thin tube with a camera to visualise higher into your canal. Surgery may be recommended in persistent or chronic cases.