What is Urine infection in children, what are their symptoms, and how to prevent it?

Urinary tract infections

Urine infection is one of the most common infections in babies and children. However, detecting its signs in time and knowing how to avoid it is vital so that it does not leave sequelae in the kidneys of the little ones.

When a young child suffers from a urine infection, it can sometimes go unnoticed, especially in children under two years of age. It happens because the most common alarm signals in adults (such as itching when urinating and pain in the lower back) do not appear at young ages, which can delay diagnosis and end up causing kidney damage. 

Early diagnosis and current antibiotic treatments help ensure the child’s full recovery and that the infection does not have greater importance.


Urinary infection occurs in areas that make up the urinary system, such as the kidney, the urinary tract, the bladder or the urethra. Urine infections can give signs differently depending on the child’s age and whether the disease is in the upper or lower urinary tract.

If it affects the urethra or the bladder, it is known as cystitis or lower urinary tract infection.

Symptoms of urine infection in babies:

The main symptom is usually fever without an apparent cause (no cold, diarrhoea or other symptoms).

Other non-specific symptoms of a urine infection may be lack of appetite, the child not gaining weight, vomiting, abdominal pain, irritability or excessive sleep.

The possibility that a febrile illness is the consequence of urine infection in an infant makes paediatricians often analyse the urine of tiny babies when they have a fever. However, we do not have a specific focus (or almost all fever cases in babies under three months).

Symptoms of urine infection in young children

There may also be a fever from age two, mainly if it affects the upper urinary tract (pyelonephritis).

Other symptoms related to this alteration can be abdominal pain in the lower belly area, pain in the lower back or voiding symptoms such as frequent urination and burning when peeing.

In some cases, the urine may have changes in colour and odour.

Tests are done to diagnose urine infection in children:

The most important test to diagnose a urine infection correctly is the urine analysis, especially the culture, which we call a urine culture test.

Urine collection must be meticulous since other germs colonise the genital area. If a sufficiently “clean” group is not achieved, the culture may be contaminated, and we will not be able to determine the germ with evidence.

Meningitis manifest in children

With urine, it is possible to carry out rapid tests – urine strips – and the first analysis under a microscope – urine sediment – ​​which will give us a lot of information. 

Renal ultrasonography may also be a helpful test if pyelonephritis is suspected or present. It helps to define the degree of involvement of the kidneys by the infection and is also used to follow its evolution.

Depending on the severity of the infection, several weeks later, it may be necessary to evaluate the functionality of the kidney and the presence of scars due to illness through other examinations.

Treatment of urine infection in children:

A urinary tract infection requires antibiotic treatment in most cases. It usually starts when there is suspicion of urine infection and is later adjusted based on the urine culture result.

Usually, infections are “very appreciative” of treatment, so the fever and voiding symptoms often stop when starting medication.

Cause of urine infection in a child:

The most frequent complication if the diagnosis is not made in time or is not treated is kidney injury with scars, which can cause kidney failure or high blood pressure in adulthood.

Relapses can be frequent, especially if there are previous congenital lesions. And babies less than a month old can end up with a generalised infection (sepsis or septicemia) if they are not treated. That is why reacting and seeking medical solutions in time is so important.

Urinary tract infections are caused by bacteria of intestinal origin found in the perineal area (on the skin around the genitals and anus). These bacteria enter the urinary system through the urethra, reaching the bladder and kidney.

The most frequent bacteria is Escherichia coli; other pathogens are Proteus and Klebsiella.

Urine may back up from the bladder towards the kidneys: this is called vesicoureteral reflux. It is usually caused because the valves that connect the ureters to the bladder are immature and allow urine to flow backwards.

This condition predisposes to urine infections, allowing germs to ascend through the urinary tract. Repeated infections could damage the kidneys. There are different degrees of reflux depending on the maturity of the valves and the dilation in the ureters they cause. Most resolve spontaneously during the first years of life; in a few cases, this requires surgical intervention.

Although the resolution is usually spontaneous, the problem is that they predispose to urinary infections, which can repeatedly damage the kidney. It is the main reason for monitoring reflux and trying to prevent and diagnose urine infections early if they occur.

Methods to prevent urine infections in children:

  • Urine infection is much more frequent in male children under one year of age, perhaps due to their natural phimosis (narrowing of the foreskin), where bacteria accumulate if careful hygiene is not maintained in this area.
  • From the age of three, it is more frequent in girls due to an anatomical issue: the anus is closer to the urinary duct in them, so germs can have it “easier”.
  • Change the diaper frequently in babies, do not wait for it to be “heavy”.
  • Take care of Intimate hygiene measures and teach girls to clean themselves from the vulva to the anus and not the other way around.
  • Use cotton underwear.
  • Offer them water often.
  • In the case of children, phimosis could favour the presence of microorganisms.