Pain after a bowel movement: causes, red flags and when to get it checked

Pain that comes on or persists after passing a stool is most often caused by a small tear in the lining of the anus (an anal fissure) or by piles (haemorrhoids). Both are common and usually respond to simple measures such as keeping stools soft and avoiding straining.

The way the pain behaves is the best guide. A sharp, cutting pain on passing the stool followed by hours of burning or aching points to a fissure. A feeling of fullness, lumps, itching and bright red blood suggests piles. Pain that is constant, comes with a high temperature or a new swelling, or does not improve within about a week of self-care needs assessment, because the cause may not be a simple fissure or pile.

The NHS describes the main symptoms of an anal fissure as severe, sharp pain when you poo, burning pain after you poo that may last for several hours, and bright red blood in the toilet or on the paper. It says fissures are more common in people aged 15 to 40 and in young children, and that you may be more likely to get one if you are constipated, have a lot of diarrhoea, are pregnant or have given birth vaginally, or have inflammatory bowel disease or a sexually transmitted infection such as syphilis or herpes.

Self-care recommended by the NHS includes paracetamol or ibuprofen for pain, drinking lots of fluid and eating plenty of fibre to keep stools soft, a warm shallow bath after you poo, keeping the area clean and dry, and not ignoring the urge to go. If symptoms are getting worse or there is no improvement after 7 days of treating it yourself, see a GP.

Treatment from a GP can include laxatives, medicines to ease pain after you poo, and a cream that helps healing which may be used for up to 8 weeks. If those do not work or fissures keep coming back, the NHS says a procedure may be recommended, such as an injection to relax the anal muscle or a small cut in the muscle, done under general anaesthetic. Referral may also be offered if the GP is not sure of the diagnosis or if examination is too painful.

Piles are lumps inside and around the anus. The NHS lists bright red blood after you poo, an itchy anus, a feeling that you still need to poo after going, mucus in the underwear or on toilet paper, lumps around the anus and pain around the anus as symptoms. They can be pea-sized or larger, and pink or purple.

Self-care includes gently pushing a pile back inside if you can, taking paracetamol for pain, an ice pack wrapped in a towel, fluid and fibre, a warm bath, and keeping the area clean and dry. The NHS advises against ignoring the urge to poo, pushing too hard, painkillers containing codeine because they cause constipation, and ibuprofen if your piles are bleeding. A pharmacist can suggest creams and laxatives.

The NHS says to see a GP if piles are getting worse, do not improve with home treatment, keep coming back, or you notice a change around the anus that is not normal for you. Painless bleeding from the bottom, pus leaking from the piles, a very high temperature or feeling unwell with shivering needs urgent advice.

When pain is not typical of a fissure or piles, a clinician considers other possibilities. The table summarises those that appear in NHS and Guts UK material, as a guide to why persistent pain should be examined rather than assumed to be a fissure.

Most cases can wait for a routine GP appointment if they are improving, but some features should not.

• You are bleeding non-stop, there is a lot of blood or large clots, or you have severe pain: the NHS says to go to A&E or call 999.

• Pain with a very high temperature, feeling hot, cold or shivery and generally unwell, or pus leaking: the NHS says to ask for an urgent GP appointment or call NHS 111.

• Painless bleeding from the bottom, or black or dark red poo, or bloody diarrhoea.

• A new lump or change around the anus that is not normal for you, or pain that persists beyond about a week of self-care.

• Weight loss, tiredness, a change in bowel habit lasting several weeks or a lump in the tummy: the NHS says to see a GP, as these can be signs of bowel cancer.

Because constipation and straining underlie most fissures and piles, keeping stools soft is the main preventive step. The NHS advice is to eat a healthy balanced diet with enough fibre, drink plenty of fluid, avoid too much alcohol and caffeine, be active, keep to a regular toilet routine and not delay the urge to go. Resting your feet on a low stool can make passing a stool easier.

If you take medicines that cause constipation, such as opioid painkillers, the NHS says to see a GP rather than stop them yourself. Spending less time on the toilet and not straining are also recommended for people with piles.