Constipation in children: why it happens, soiling, laxatives and when to see the GP

Normal bowel habits vary: NHS inform notes that some infants pass stools several times a day while others pass them only a few times a week. Constipation is about a change from that child's pattern plus difficulty or pain. The NHS lists the following signs that a child may be constipated.

• fewer than 3 poos in the last week

• large, hard poo, or poo that looks like rabbit droppings or little pellets

• straining or pain when pooing

• some bleeding during or after a poo because the poo is large and hard

• poor appetite, or stomach pain that improves after a poo

The NHS explains that in a child over 1 year, soiled pants can be a sign of constipation, because runny poo may leak around the hard, constipated poo. This is called overflow soiling. Alder Hey describes faecal impaction as stool building up over days and weeks, leading to large painful motions and accidents from watery stool seeping around hard stool that does not move.

It matters because the wrong conclusion, such as a tummy bug or a child misbehaving, delays the right treatment. The NHS adds that laxative treatment may make overflow soiling worse before it gets better.

The NHS says there are many possible causes and sometimes none is obvious: not enough high-fibre foods, not enough fluids, feeling pressured or regularly interrupted during potty training, and worry about changes such as moving house, a new baby or starting nursery or school. NHS inform adds fear about using the toilet and difficulty with toilet training, and says babies who have too much milk are more likely to get constipation.

Pain is the engine of the cycle. The NHS says that if pooing hurts a child may not want to try, which creates a vicious circle: the more they hold back, the more constipated they get. Alder Hey lists holding in because of reluctance to use an unfamiliar or dirty toilet, low exercise, routine changes, a family history and certain medicines as further factors.

NHS inform says that in rare cases constipation in babies and children can be a sign of an underlying condition and names Hirschsprung's disease, anorectal malformation, spinal cord abnormalities including spina bifida and cerebral palsy, and cystic fibrosis. NICE guideline CG99 applies to children whose constipation has no known cause, called idiopathic constipation, once underlying causes have been excluded by history and examination, and it says a child with any red flag symptom should not be treated for constipation but referred urgently. One example of a red flag is failing to pass the first stool (meconium) within 48 hours of birth in a term baby; another is a child under 1 year whose constipation does not respond to optimum treatment within 4 weeks, who should be referred urgently.

Alder Hey advises that children who have a swollen tummy, vomiting or pass a lot of blood alongside constipation should be seen in the Emergency Department.

The NHS says to take a child you think is constipated to a GP, that treatment depends on age, and that laxatives are often recommended for children eating solid foods alongside diet and lifestyle changes. It says to keep trying for the months it may take, and that a GP may advise continuing laxatives for a while so poo stays soft. NICE guideline CG99 says dietary interventions alone should not be the first-line treatment for idiopathic constipation, and that families should be told that although there is a suitable treatment, it may take several months for the condition to be resolved.

Alder Hey says medicines that help the bowel absorb water may need to be taken for weeks or months for the best results. Doses are decided by the prescriber for the child's age and weight.

The NHS and Alder Hey suggest a number of practical steps for prevention and support.

• Offer plenty of fluids; breastfed babies not yet on solids can have more breastfeeds, and formula-fed babies extra water between feeds, which must be cooled boiled water under 6 months (NHS).

• Include a variety of foods with plenty of fruit and vegetables; Alder Hey suggests grating vegetables into favourite meals and mentions prunes.

• Build a routine of sitting on the potty or toilet after meals or before bed and praise the child whether or not they poo (NHS).

• Make sure feet rest flat on the floor or a step (NHS).

• Ask whether the child feels worried about using the toilet at nursery or school (NHS).

Alder Hey says symptoms are normally managed by families with help from a health visitor or school nurse, and that a child who has not passed stool for five or more days should see the GP because further treatment may be necessary. The NHS says a health visitor or GP can offer tips on soiling. For most families the pathway is GP or health visitor first; referral to a paediatric team is reserved for children whose constipation has not responded or who have warning features.