Pyelonephritis or Kidney Infection (Child)

Illustration showing a child's kidneys, ureter and bladder.A type of infection of one or both kidneys is called pyelonephritis. It is usually caused when bacteria or a virus gets into the kidneys. The bacteria or virus can enter the kidney(s) from the bladder or from blood traveling from other parts of the body.

Common causes for this problem include:

  • Not keeping the genital area clean and dry, which promotes the growth of bacteria.

  • In young girls: wiping in the back to front. This drags bacteria from the rectum toward the urinary opening (urethra).

  • Wearing tight pants or underwear. This allows moisture to build up in the genital area, which helps bacteria grow.

  • Sensitivity of some children to the chemicals in bubble baths. These can enter the urinary opening and can lead to a urinary infection.

  • “Holding” the urine for long periods of time

  • Dehydration

A first-time urinary tract infection is not unusual in a female child. However, recurrent infections in a girl or a first-time infection in a boy require further testing.

Kidney infections can cause symptoms similar to a bladder infection. The infection can cause one or more of these symptoms:

  • Pain (or burning) when urinating

  • Having to urinate more often than usual

  • Bedwetting or urinating in underwear (by a child who is toilet-trained)

  • Blood in urine (pink or red in color)

  • Abdominal pain or discomfort, usually in the lower abdomen

  • Pain in the side or back

  • Pain above the pubic bone

  • Fever or chills

  • Vomiting

  • Irritability, especially in infants

  • Refusing to eat

  • Poor weight gain

Children younger than 2 years old may only have a high fever without other symptoms involving the urinary tract (such as blood in the urine, pain when urinating, etc).

Children who are older than 2 months of age and not vomiting are treated with oral (liquid, pills) antibiotics. These are started right away. If a culture was done, you will be told if the treatment needs to be changed. If directed, you can call to find out the results

Based on a child’s age (less than 2 months), overall health, or how severe the infection, he or she may need to be admitted to the hospital.

Home care


  • The healthcare provider will prescribe medicine to treat the infection. Follow all instructions for giving this medicine to your child. Use the medicine as instructed every day until it is gone. Don’t stop giving it to your child even if he or she feels better. Never give your child aspirin unless told to by the healthcare provider.

  • For children ages 2 and up: You can give acetaminophen or ibuprofen for pain, fever, fussiness, or discomfort, if allowed by the healthcare provider.

  • If your child has chronic liver or kidney disease, talk with your healthcare provider before giving these medicines. Also talk with your provider if your child has ever had a stomach ulcer or gastrointestinal bleeding, or is taking blood thinners. Contact your child’s healthcare provider before starting or stopping any medicine (over-the-counter or prescription).

General care

  • Your child should stay home from school and rest in bed until his or her fever breaks and your child feels better, or as advised by the doctor.

  • Make sure your child drinks plenty of fluids. Or, make sure your baby feeds often. This is to prevent dehydration. Ask your doctor how much water your child should try to drink daily.

  • Keep track of how often your child urinates. Note the urine color and amount.

  • Do what you can to get your child to urinate at least every 3 to 4 hours during the day. Make sure he or she does not delay. Holding urine and overstretching the bladder can make your child’s condition worse.

  • Tell your child to completely empty the bladder each time. This will help flush out bacteria.

  • Have your child wear loose clothes and cotton underwear.

  • Make sure that your child drinks enough fluids. Give your child cranberry juice if advised by the healthcare provider.

  • Females should avoid taking bubble baths. Sensitivity to the chemicals in bubble baths can irritate the urethra.

  • Make sure your child wipes from front to back after using the toilet. Wipe your baby from front to back during diaper changes.

  • Make sure your son’s penis is cleaned regularly. If he isn’t circumcised, have him retract (pull back) the foreskin when cleaning.


  • Teach your daughter to wipe from front to back after using the toilet.

  • Teach your son to clean his penis regularly. If he isn’t circumcised, teach him to retract (pull back) the foreskin when cleaning.

  • Make sure diapers aren’t tight. If you use cloth diapers, use cotton or wool protectors rather than nylon or rubber pants. 

  • Change soiled diapers right away. Keep the genital region clean and dry.

  • Make sure your child urinates when needed, and does not hold it in. Do what you can to get your child to urinate at least every 3 to 4 hours during the day. Make sure he or she does not delay. Holding urine and overstretching the bladder can make your child’s condition worse.

  • Make sure your child avoid wearing tight-fitting pants and underwear.

  • Encourage your child to urinate in a steady stream rather than starting and stopping during urination. This helps to empty the bladder all the way.

  • Keep your child’s bath water free of shampoo, or other soaps. Wash the child’s genital area with no or very gentle soap (not bar soap) and rinse well with water.  Gently dry.

  • Constipation can make a urinary tract infection more likely. Talk to your child’s doctor if your child has trouble with bowel movements.

Follow-up care

Make a follow-up appointment as directed by your child’s healthcare provider. Close follow-up and further testing is very important to find the cause and to prevent future infections.

If your child had a urine culture during this visit, you will be contacted if your child’s treatment needs to be changed. If directed, you can call to find out the results.

If you had an X-ray, CT scan, or another diagnostic test, you will be notified of any new findings that may affect your child’s care. 

Call 911

Call 911 if any of the following occur:

  • Trouble breathing

  • Confused

  • Very drowsy or trouble awakening

  • Fainting or loss of consciousness

  • Rapid or very slow heart rate

  • Weakness, dizziness, or fainting

When to seek medical advice

Call your child's healthcare provider right away if any of these occur:

  • Not feeling better within 1 to 2 days  after starting antibiotics

  • 2 years old or older on antibiotics: Has a fever of 102.2°F or higher (39°C) or has a fever that lasts for more than 2 days or as directed by the doctor.

  • Any symptoms that continue after 3 days of treatment

  • Increasing pain in the stomach, back, side, or groin area

  • Trouble urinating or decreased urine output

  • No urine for 8 hours, no tears when crying, "sunken" eyes, or dry mouth.

  • Vomiting

  • Bloody, dark-colored, or foul-smelling urine

  • Not able to take prescribed medicine due to nausea or any other reason

  • In girls: vaginal discharge, pain, swelling or redness in the labia (outer vaginal area)

  • In infants: Increase in irritability or fussiness or unable to calm down

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