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Urinary tract infection, children

Page last reviewed: 13/07/2011

A urinary tract infection (UTI) is a common type of infection that occurs in the urinary tract (see below). The symptoms of a UTI in a child include:

  • high temperature (fever) of, or above, 38°C (100.4°F)
  • pain, or a burning sensation, during urination (dysuria)
  • a frequent need to urinate

The urinary tract

The urinary tract is made up of:

  • the kidneys, which extract waste materials from the blood and convert it into urine
  • the ureters: the tubes that run from the kidney to the bladder
  • the bladder: a 'balloon-shaped' organ that is used to store urine
  • the urethra: the tube that runs from the bladder through the penis (in males) or vulva (in females) through which urine passes

UTIs develop when part of the urinary tract becomes infected, usually by bacteria. Bacteria can enter the urinary system through the urethra or, more rarely, through the bloodstream.

In many cases, there is no apparent cause of your child's urinary tract infection. However, there are several factors that increase the risk of a UTI developing.

These include:

  • constipation: which can place pressure on the bladder, making it more vulnerable to infection
  • dysfunctional voiding: a relatively common childhood condition where a child 'holds on' to their urine even though they have an urge to urinate. See causes for more information about constipation and dysfunctional voiding.

Types of urinary tract infection

There are two types of UTI:

  • A lower UTI is an infection of the lower part of the urinary tract, which includes the bladder and the urethra. An infection of the bladder is called cystitis, and an infection of the urethra is known as urethritis.
  • An upper UTI is an infection of the upper part of the urinary tract, which includes the kidneys and the ureters. Upper UTIs are potentially more serious than lower UTIs because there is a risk of kidney damage. An infection of the kidneys is known as pyelonephritis.

How common are urinary tract infections in children?

UTIs in children are less common than they are in adults (particularly adult women).

Around 11% of girls and 4% of boys will have a UTI before they are 16 years of age. UTIs are more common in girls, except during the first six months of life when they are more common in boys.

Most of the UTIs that occur during childhood are lower UTIs. Only 3% of young girls, and 1% of young boys, develop an upper UTI.


With treatment, the outlook for a child with a UTI is excellent. UTIs can easily be treated with antibiotics, and the risk of complications is low.

However, in UTI cases, prompt diagnosis and treatment is very important. If left untreated, UTIs (particularly upper UTIs) can cause a number of serious problems, including kidney damage or even kidney failure.

Older children with a UTI can usually be treated at home. As a precaution, very young children with a UTI (those who are less than three months of age) are treated in hospital.

Kidneys are a pair of bean-shaped organs located at the back of the abdomen. They remove waste and extra fluid from the blood and pass them out of the body as urine.
The bladder is a small organ near the pelvis that holds urine until it's ready to be passed from the body.
The urethra is a tube that carries urine from the bladder to the outside of the body.
The liver is the largest organ in the body. Its main jobs are to secrete bile (to help digestion), detoxify the blood and change food into energy.
Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.
Constipation is when you pass stools less often than usual, or when you are having difficulty going to the toilet because your stools are hard and small.
Contagious is when a disease or infection can be easily passed from one person to another.
Antibiotics are medicines that can be used to treat infections caused by micro-organisms, usually bacteria or fungi. Amoxicillin, streptomycin and erythromycin are examples of antibiotics.

Page last reviewed: 13/07/2011

The symptoms of urinary tract infections (UTIs) during childhood can differ depending on the age of your child.

Children under three months

In children who are under three months of age, the symptoms of a UTI (ranked in order of most common to least common) are:

  • high temperature (fever) of, or above, 38°C (100.4°F)
  • vomiting
  • lethargy (lack of energy)
  • irritability
  • poor feeding
  • failure to thrive (not developing at the expected rate)
  • abdominal (stomach) pain
  • yellowing of the skin and whites of the eyes (jaundice)
  • blood in their urine
  • unpleasant smelling urine

Older children

In children who are older than three months, but are not old enough to talk, the symptoms of a UTI (ranked in order of most to least common) are:

  • high temperature (fever) of, or above, 38°C (100.4°F)
  • abdominal (stomach) pain
  • a feeling of tenderness around their pelvis
  • vomiting
  • poor feeding
  • lethargy (lack of energy)
  • irritability
  • blood in their urine
  • unpleasant smelling urine
  • failure to thrive (not developing at the expected rate)

In children who are old enough to talk, the symptoms of a UTI (ranked in order of most to least common) are:

  • a frequent need to urinate
  • pain, or a burning sensation, during urination (dysuria)
  • deliberately holding in their urine
  • a change in their normal toilet habits, such as wetting themselves, or wetting the bed
  • a feeling of tenderness around their pelvis
  • high temperature (fever) of, or above, 38°C (100.4°F)
  • a general sense of feeling unwell
  • blood in their urine
  • unpleasant smelling urine
  • cloudy urine

When to seek medical advice

You should always contact your GP if your child develops any of the symptoms that are listed above.

Most UTIs that occur during childhood are mild and are not a cause for concern, but they do usually require treatment with antibiotics in order to reduce the length of infection and to reduce the risks of complications developing.

Page last reviewed: 13/07/2011

Urinary tract infections (UTIs) are caused when bacteria enter and infect the urinary tract (the system of ducts and channels that runs from the kidneys to the penis, or vulva, and through which urine passes).

Bacteria, such as Escherichia coli (E. coli) living in your child's colon, are often the cause of UTIs. The bacteria enter through the opening of the urethra (the tube that runs through the bladder to the penis or vulva) and then multiply in the bladder. This can sometimes happen to children who are still being toilet trained.

The bacteria can be inadvertently spread from their anus (the opening through which faeces are passed) to their urethra. This can sometimes happen if, when wiping their bottom after going to the toilet, the soiled toilet paper comes into contact with the child's genitals. Young girls are at more risk than boys from getting UTIs in this way because there is less distance between their anus and urethra.

There are several conditions that can increase the risk of UTIs occurring. These are outlined below.


Constipation does not usually have any obvious causes, but it can sometimes result from a lack of fibre in a child's diet. Constipation is a relatively common condition among children.

Constipation can cause the rectum (the part of the large intestine that connects to the anus) to swell, which can put pressure on the bladder, preventing it from emptying normally. The remaining urine can then become infected by bacteria.

See the Health A-Z topic about constipation for more information and advice about the condition.

Dysfunctional voiding

Dysfunctional voiding is a relatively common condition among children. It occurs when a child 'holds on' to their urine even though they have the urge to urinate. This can occur as a result of nerve damage, but it can also be due to habit, which can be difficult for the child to break.

For example, young children at playschool, or primary school, may be nervous or embarrassed about asking to use the toilet, so they may hold onto their urine until they go home.

Children usually grow out of dysfunctional voiding as they start to adopt more regular bathroom habits. However, some children may need special training.

In many cases, there is no clear cause of a UTI. It seems that some children are simply more sensitive, or vulnerable, to the bacteria that can cause a UTI than others.

Vesicoureteral reflux

Vesicoureteral reflux is an uncommon condition in which urine leaks back up from the bladder and into the ureters and kidneys. It is estimated that one in 50 girls and one in 200 boys, who are under 12 years of age, are affected by vesicoureteral reflux.

There are two types of vesicoureteral reflux:

  • Primary vesicoureteral reflux is caused by a defect that is present before birth (congenital). There is usually a valve between the bladder and the ureters that prevents urine leaking back out of the bladder. In children who have primary vesicoureteral reflux, the valve does not function properly, and urine is able to flow out of the bladder and back up the ureter to the kidney.
  • Secondary vesicoureteral reflux is caused by a condition that arises after birth. For example, when urine is blocked from flowing out of the bladder, or when a lower urinary tract infection (UTI) causes the ureters to become so inflamed and swollen that the one-way valves in the ureters fail, allowing urine to flow both ways.

The danger with vesicoureteral reflux is that a lower UTI can quickly turn into a more dangerous upper UTI because infected urine can move out of the bladder and back into the ureters and kidneys.

Primary vesicoureteral reflux usually clears up in children as they get older. However, if it is felt that a child has a high risk of developing upper UTIs, they may be prescribed an antibiotic to take in the long-term.

Page last reviewed: 13/07/2011

Urine sample

Children with the symptoms of a urinary tract infection (UTI) should always have their urine tested because an accurate diagnosis is important for treatment.

An exception may be made for girls who are over three years of age and have the typical symptoms of cystitis (infection of the bladder), such as urinating more frequently and pain when passing urine.

A urine test is also useful for ruling out other conditions that can cause similar symptoms, such as type 1 diabetes.

If your child has a temperature of 38°C (100.4°F) or above (a fever), and their GP is unable to find an obvious cause for it, your child's urine should be tested within 24 hours.

If your child does not have a fever, but has other symptoms of a UTI, a urine test will still be required. However, the urine test does not need to be carried out as quickly, and it might be reasonable to wait more than 24 hours to have it done.

In young children, it is very important to make an accurate diagnosis. However, it can be difficult to obtain a clean urine sample from young children because they are often unable to pass urine into a specimen bottle. Also, if you, or they, touch the inside rim of the specimen bottle with your (their) hands, it will affect the quality of the sample. Therefore, it may be necessary to carry out the test in hospital.

Testing in hospital usually involves placing a small plastic tube, called a catheter, into your child's urethra (the opening in the penis or vagina which urine flows out of). The catheter will be guided up into the bladder and used to drain out a small sample of urine for testing.

Further testing

Further testing is usually only required if your child's UTI symptoms are different from the usual symptoms (atypical). Examples of atypical symptoms include:

  • being seriously ill
  • reduced urine flow
  • a noticeable lump or mass in their abdomen (stomach) or bladder
  • testing showed that the bacteria has spread from their urinary tract to their blood
  • they failed to respond to antibiotic treatment within 48 hours
  • the infection was caused by bacteria other than the Eschericia coli (E. coli) bacteria

Further testing is also required if your child has previously had:

  • two or more upper UTIs
  • one upper UTI, plus one or more lower UTIs
  • three or more lower UTIs

Atypical symptoms and recurring UTIs could be due to underlying problems with your child's urinary tract infection that will require further investigation.

The types of tests and procedures that are commonly used to investigate the urinary tract are described below.

Ultrasound scan

An ultrasound scan is usually the first procedure that is used to assess the urinary tract. The ultrasound scan uses sound waves to build up a picture of the inside of your child's body.

An ultrasound scan is a useful way of assessing whether there are any obvious abnormalities in your child's urinary tract, such as an unusually narrow ureter (the tube that runs from the kidneys to the bladder) or a bladder stone, or kidney stone.


A dimercaptosuccinic acid (DMSA) scan is a type of scan that is used to assess the state of the kidney. A DMSA scan is usually carried out six months after an acute atypical UTI (a UTI with unusual symptoms) or after the last episode of a series of recurring UTIs.

A DMSA scan is used to assess whether your child's kidneys have been damaged, or if there are any abnormalities with the kidneys that are making them vulnerable to recurring UTIs. DMSA is a mildly radioactive substance that shows up on a special camera, known as a gamma camera.

During the procedure, your child will be injected with DMSA. After an hour, the DMSA will build up inside the kidneys. DMSA only attaches itself to healthy tissue, so it is a useful method of locating any damaged kidney tissue.

The gamma camera is used to take a series of pictures of your child's kidneys. It usually takes about 30 minutes to complete the scan. During this time it is important for your child to remain as still as possible, so it may be a good idea to bring their favourite book or toy to help them to relax during the scan.

A DMSA scan is not painful because local anaesthetic is used to numb the site of the injection. However, the gamma camera is quite large, so younger children may find the experience upsetting. Explaining exactly what will happen and what to expect before the scan may help to reassure your child.

After the scan, the DMSA will pass harmlessly out of your child's body in their urine. Their urine will be slightly radioactive, but it is not harmful to your child or other people. However, as a precaution, it is recommended that you wash your hands after changing your child's nappy, and that you dispose of their nappies in a sealed plastic bag.

Micturating cystourethrogram (MCUG)

Micturating cystourethrogram (MCUG) is a similar procedure to a DMSA scan, except that it is used to study the bladder rather than the kidneys.

MCUG is used to check that your child does not have vesicoureteral reflux (a condition where urine leaks back up from the bladder towards the kidneys). As with a DMSA scan, it is important for your child to stay as still as possible during the MCUG procedure. Very young children and babies may need to be wrapped tightly in blankets to help prevent them moving during the procedure.

During MCUG, your child will lie on a bed, or treatment table, and a catheter will be used to pass a special type of liquid, known as a contrast agent, into their bladder. Like DMSA, the contrast agent shows up very clearly on an X-ray.

An X-ray film (a continuous film, rather than a series of single images) will then be taken as the contrast agent is passed out of your child's bladder, in the same way that their urine passes out.

If the X-ray film shows some of the contrast agent leaking back out of the bladder towards the kidneys, it is likely that your child has vesicoureteral reflux.

Most cases of vesicoureteral reflux resolve without the need for treatment as a child gets older. It may be recommended that your child is given a long-term course of low-dose antibiotics to help prevent them from developing another UTI, until the condition resolves.

The MCUG procedure is not painful and takes around 30 minutes to complete. However, it is likely that your child will feel mild discomfort when the catheter is first inserted into their urethra.

The X-rays will expose your child to a low dose of radiation that is entirely safe. The levels of radiation that are used are the same as the amount of radiation your child would be exposed to by natural sources (background radiation) over the course of three to six months.

Page last reviewed: 13/07/2011

Children under three months old

If your child is less than three months old, they will be referred to a paediatrician (a doctor who specialises in the care of children). If your child has a urinary tract infection (UTI), they will usually be treated in hospital using an intravenous drip (where a tube containing antibiotics is directly connected to their vein). Your child should recover from the UTI within 24 to 48 hours.

Children over three months old

If your child is over three months old, and they have a UTI, and it is felt that there is a risk of serious complications occurring, they will be referred to hospital for treatment.

Signs that can indicate a risk of your child developing serious complications from a UTI include:

  • a recurring high temperature (fever) of 38°C (100.4°F) or above
  • dehydration
  • vomiting
  • a known condition that affects their urinary system
  • a history of kidney disease in your family

If your child is very young, your GP may decide to refer them for hospital treatment, even if there is not an obvious risk that they will develop serious complications.

If it is felt that there is no risk of serious complications developing, or if the risk is low, you may be able to treat your child at home. The infection can be treated using oral antibiotics, and paracetamol can be used to treat any symptoms of fever or discomfort.

For lower UTIs, a three-day course of antibiotics is usually recommended. For upper UTIs, a seven-day course of antibiotics is usually recommended. Children who are unable to swallow tablets or capsules can be given antibiotics and paracetamol in liquid form.

Your child should recover from the UTI within 24 to 48 hours. However, it is very important that they finish the prescribed course of antibiotics in order to prevent the infection recurring.

After taking antibiotics, some children may experience side effects. However, any side effects will usually pass after your child stops taking the antibiotics. Side effects may include:

  • nausea
  • vomiting
  • upset stomach
  • diarrhoea
  • loss of appetite

A very small number of children (less than one in 1,000) may experience a severe allergic reaction to antibiotics that contain penicillin. Symptoms of an allergic reaction to penicillin include:

  • a rash
  • swelling of the hands, feet and face
  • shortness of breath

If your child experiences these symptoms, you should call your GP immediately for advice.


It is important to treat constipation in children promptly because it is a major risk factor for developing UTIs.

As with babies and adults, children with constipation will first be advised to change their diet. If this fails, laxatives can be prescribed. An osmotic laxative is usually prescribed, followed, if necessary, by a stimulant laxative.

Osmotic laxatives increase the amount of fluid in your child's bowels. This helps to soften your child's stools, making it easier for them to pass them out of their body.

Stimulant laxatives stimulate the muscles that line the digestive tract, helping to move stools along your child's large intestine to their anus (the point at which waste products leave the body).

As well as eating plenty of fruit, older children should have a well balanced diet that contains vegetables and wholegrain foods, such as wholemeal bread and pasta.

For further information about how to treat constipation in children, see the Health A-Z topic about Constipation - treatment.

Page last reviewed: 13/07/2011

It is not possible to prevent all urinary tract infections (UTIs) that occur in children, but the advice listed below may help to reduce their frequency.

  • Encourage your child to wipe their bottom from front to back. This will help to minimise the chances of bacteria entering the urethra (the tube that urine passes through).
  • Breastfeeding your baby may lower the risk of them developing a UTI. However, the effect appears to be cumulative (takes time to build up), only providing protection after three months of breastfeeding.
  • Encourage boys to clean around their foreskin regularly. Bacteria can build up there and enter the urethra. If your child's foreskin is still fixed (does not retract), you should not attempt to clean under it because doing so may damage the surrounding area.
  • Encourage children to go to the toilet regularly. They should go at least every four hours, and before having a bath and going to bed.
  • Avoid nylon and other types of synthetic underwear. These can help to promote the growth of bacteria. Loose-fitting cotton underwear should be worn instead.
  • Drinking cranberry juice can help prevent UTIs, but be careful to limit the amount that your child drinks because too much can cause diarrhoea. Three glasses of low-sugar cranberry juice a day is a safe amount for most children. Cranberry juice is not suitable for children with diabetes, or for those taking warfarin (a blood-thinning medicine). Higher strength cranberry capsules are also available, but they are not suitable for children who are under 12 years of age.

Recurrent urinary tract infections

A small number of children have recurring UTIs. If your child has previously had a UTI, it is important that both you and they watch out for the return of any associated symptoms.

Any symptoms should be reported as soon as possible so that a diagnosis can be confirmed and treatment can begin.

Page last reviewed: 13/07/2011

Kidney scarring

A small number of children who experience an upper UTI, which typically affects the kidney, may experience some scarring of their kidneys. Scarring is more likely in children under two years of age than in older children.

Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.

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