Definition & Facts of Bladder Infection in Children

What is a bladder infection?

A bladder infection is an illness that is usually caused by bacteria. Bladder infections are the most common type of urinary tract infection (UTI) in children. A UTI can develop in any part of your child’s urinary tract, including the urethra, bladder, ureters, or kidneys.

All healthy children have some bacteria on their bodies and in their bowels. Occasionally, bacteria can get into the bladder and start an infection. Children of any age can and do develop bladder infections, including infants.

Your child’s body has ways to defend against infection. For example, urine normally flows from your child’s kidneys, through the ureters, to the bladder. Bacteria that enter the urinary tract are flushed out when your child urinates. This one-way flow of urine keeps bacteria from infecting the urinary tract.

Sometimes the body’s defenses fail and the bacteria cause a bladder infection. If your child has symptoms of a bladder infection, or has a fever without a clear cause, see a health care professional within 24 hours.

Female doctor gently touches the belly of a young girl who lies on an examining table.
Bladder infections are common in children, especially girls. Quick treatment is important to prevent a kidney infection.

Getting treatment right away for an infection in your child’s urethra or bladder can prevent a kidney infection. A kidney infection can develop from an infection that moves upstream to one or both kidneys. Kidney infections are often very painful and can be dangerous and cause serious health problems, so it’s best to get early treatment when your child has a bladder infection.

A health care professional is likely to treat your child’s bladder infection with antibiotics, a type of medicine that fights bacteria. It’s important for your child to take every dose on time and to finish all of the medicine.

Is there another name for a bladder infection?

Bladder infections are also called cystitis. Sometimes people use the more general term, urinary tract infection (UTI) to mean a bladder infection, although UTIs can occur in other parts of the urinary system. A UTI that affects the kidneys is called pyelonephritis.

How common are bladder infections in children?

Bladder infections are a common reason that children visit a health care professional. Each year, about 3 in 100 children develop a UTI, and most of these infections are bladder infections.1

  • Babies under 12 months old are more likely to have a UTI than older children.
  • During the first few months of life, UTIs are more common in boys than girls.
  • By age 1, girls are more likely to develop a UTI than boys—and girls continue to have a higher risk throughout childhood and the teen years.2

Which children are more likely to develop a bladder infection?

Girls are much more likely to develop bladder infections than boys, except during the first year of life. Among boys younger than age 1, those who have not had the foreskin of the penis removed, called a circumcision, have a higher risk for a bladder infection. Still, most uncircumcised boys will not get a bladder infection.

In general, any condition or habit that keeps urine in your child’s bladder for too long may lead to an infection.

Other factors that may make your child more likely to develop a bladder infection include

  • abnormal bladder function or habits, such as
    • overactive bladder—a treatable condition that often goes away as your child grows older
    • not emptying the bladder fully
    • waiting too long to urinate
  • constipation—fewer than two bowel movements a week or hard bowel movements that are painful or difficult to pass
  • vesicoureteral reflux (VUR)—the backward flow of some urine from the bladder toward the kidneys during urination.
  • urinary blockage—a problem that limits the normal flow of urine, such as a kidney stone or a ureter that is too narrow. In some cases, this can be related to a birth defect.
  • poor toilet hygiene
  • family history of UTIs

Among teen girls, those who are sexually active are more likely to get a bladder infection.

Different anatomy makes girls much more likely to develop a bladder infection than boys:

  • Girls have a shorter urethra than boys, so bacteria don’t have to go as far to reach the bladder and cause an infection.
  • In girls, the urethra is closer to the anus, a source of bacteria that can cause a bladder infection.

What are the complications of bladder infections in children?

Quick treatment is likely to cure your child’s bladder infection with no complications.

If an infection in the lower urinary tract, such as a bladder infection, is not treated properly, it can lead to a kidney infection. Kidney infections that last a long time or keep coming back can cause damage to a child’s kidneys that never goes away. This damage can include kidney scars, poor kidney function, high blood pressure, and problems during pregnancy. Young children have a greater risk for kidney damage from a UTI than older children and adults.

In a few cases, a kidney infection can develop suddenly and become life-threatening, particularly if bacteria get into the bloodstream, which causes a reaction called sepsis, or septicemia.


April 2017

This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings through its clearinghouses and education programs to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.

The NIDDK would like to thank:
Saul P. Greenfield, MD, FAAP, FACS, State University of New York at Buffalo School of Medicine; Jeffrey M. Saland, MD, MSCR, Icahn School of Medicine at Mt. Sinai