Anal tear (or anal fissure)

What are the symptoms of an anal fissure?

The main symptoms are:

• severe, sharp pain when you poo
• a burning pain afterwards that can last from a few minutes to several hours
• bright red blood on the toilet paper or in the toilet
• itching or soreness around the tear
• a small skin lump near the tear, more common if the fissure has become long-standing.

Fissures are often mistaken for piles (haemorrhoids), since both can cause pain and bleeding after passing a stool. Fissure pain tends to come in sharp episodes tied to bowel movements, while pile pain, when present, is more often constant.

What causes an anal fissure, and who's at risk?

Most fissures happen when a large or hard stool overstretches and tears the anal opening, usually because of constipation. Straining, tightening (spasm) of the muscle around the anus, and severe diarrhoea can also cause a tear. You may be more likely to get an anal fissure if you:

• have constipation, which is a common cause in both adults and children
• have frequent diarrhoea
• are pregnant, or have recently given birth vaginally, which accounts for around 1 in 10 cases
• have a condition such as inflammatory bowel disease, including Crohn's disease or ulcerative colitis
• have a sexually transmitted infection, such as syphilis or herpes.

Anal fissures are common and can affect anyone, though they're most frequently diagnosed in people aged 15 to 40. Around 4 in 10 fissures that start suddenly go on to become long-standing (chronic).

Are there different types of anal fissure?

Fissures are described as acute if they've been present for less than 6 weeks, and chronic if they last longer than this. Chronic fissures are more likely to have a small skin tag or thickened tissue at the edge of the tear, and generally need more active treatment to heal.

Most fissures are 'primary', with no identifiable underlying cause, and sit at the front or back of the anus. Less commonly, a fissure is 'secondary' to another condition, such as inflammatory bowel disease, an infection or, rarely, a tumour; these are more likely to sit off to the side, or to appear as more than one tear at once.

How is an anal fissure diagnosed?

A doctor can usually diagnose an anal fissure just by asking about your symptoms and gently examining the area, often lying on your side or front. If this is too painful to continue, your doctor can usually still confirm the diagnosis without going further.

You may be referred for an examination under general anaesthetic if your doctor isn't sure of the diagnosis, if something else might be causing your symptoms, or if the muscle spasms make an examination too painful to complete while you're awake.

How is an anal fissure treated?

Most anal fissures heal by themselves within 1–2 weeks with simple self-care, in much the same way as any other small skin cut.

Self-care for a new (acute) fissure

• take paracetamol or ibuprofen for pain, and avoid codeine-based painkillers, which can cause constipation and make things worse
• If constipation is the cause, use an osmotic laxative. Speak to a pharmacist about starting a short course of an osmotic laxative (such as Macrogol). This draws water into your bowels to ensure your stool is soft and effortless to pass
• eat plenty of fibre and drink plenty of fluids to keep your stools soft
• take a warm, shallow bath after passing a stool, to relieve pain and pat (rather than rub) the area dry
• keep the area clean, washing gently with water rather than soap while it's sore
• don't ignore the urge to go to the toilet, as delaying can make stools harder to pass.

A cream containing a mild anaesthetic can help with pain, but should only be used for 5 to 7 days at a time, since longer use can irritate the skin further.

Treatment for a fissure that isn't healing (chronic)

If a fissure persists treatment moves on to relaxing the muscle around the anus (the sphincter) to improve blood flow and help the tear close:

• glyceryl trinitrate (GTN) ointment, applied twice daily for 6–8 weeks, cures around 7 in 10 people, though up to 6 in 10 get a headache as a side effect (usually short-lived)
• diltiazem cream works similarly to GTN and is a good alternative if headaches are a problem, though it can occasionally make the skin around the anus itchy
• Botox (botulinum toxin) injected into the sphincter muscle, usually as a day case under general anaesthetic, temporarily relaxes it for around 3 months and cures roughly 7 in 10 people, occasionally causing minor difficulty controlling wind.

Surgery

If other treatments haven't worked, or the fissure keeps coming back, a small operation called a lateral sphincterotomy can help. Your surgeon makes a small cut in the sphincter muscle to permanently reduce its tension, letting the fissure heal. It's usually done as a day case under general anaesthetic.

When should you see a doctor?

See a GP if you or your child's symptoms are getting worse, or haven't improved after 7 days of self-care. You should also seek advice if a fissure lasts more than 6 weeks, since it's then considered chronic and usually needs active treatment rather than self-care alone.

It's also worth getting checked if you keep getting fissures, or if you have other symptoms alongside the tear, such as ongoing changes in your bowel habits, since these can sometimes point to an underlying cause that needs its own treatment.