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Urinary tract infection (UTI) in a baby or child: the signs, the urine test, what helps, and when to call
For anyone looking after a child who may have a bladder infection: a parent, a grandparent, a foster parent, an aunt or uncle. This page passes on, by name, what the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health, says: the signs under age 2 and from age 2, how the urine is tested, antibiotics and finishing them, what helps at home, what cranberry does not do, the signs that it may have reached the kidneys, and what may help prevent the next one. It builds the questions to ask. Take only what you need today.
Right now
- Fever and chills, nausea or vomiting, or pain in the back, side, or groin: NIDDK gives these as symptoms of a kidney infection and says quick treatment is important. It does not say how fast and does not name 911.
- Symptoms of a bladder infection, or a fever without a clear cause: NIDDK says to contact a health care professional. Its older Spanish page (2017) says: within 24 hours.
- A child younger than 2 months, or a child who is vomiting: NIDDK says they may go to a hospital for antibiotics through a vein.
- Under age 2 there may be no symptoms at all. NIDDK says a urine test is the only way to know for sure.
- Do not wait it out with cranberry juice. NIDDK says cranberry products don’t treat existing bladder infections, and that waiting to seek help could result in a more serious infection that could lead to kidney damage.
If you cannot reach a provider and you are frightened for your child, go to an emergency room or call 911. That line is ours: none of the NIDDK pages names 911. This page is not for emergencies.
More help
- A fever with it: Fever in a baby or child: when to call, and what helps.
- Vomiting, or not keeping liquids down: Vomiting and diarrhea in a baby or child: fluids, and when to call.
- Constipation, which NIDDK lists among the things that make bladder infections more likely: Constipation in a baby or child: what helps, and when to call.
- Wet beds or daytime accidents without an infection: Bedwetting: what helps, what doesn’t, and when to call.
- A baby who will not stop crying: Crying baby: when the crying won’t stop.
- Writing down what happened and when: Symptom diary.
- For a visit: Get ready for your appointment. No insurance: When you need a doctor and can’t pay.
- All our free tools.
Looking after a baby or child? The pages on this site for a baby or child, on one list.
This page and its wording were written with AI (Claude) for Scarlet Beast (our AI policy). No doctor or nurse has reviewed it. The facts were read on October 10, 2026 on niddk.nih.gov, on the pages called Bladder Infection (Urinary Tract Infection—UTI) in Children: the overview and its five sections (Definition & Facts, Symptoms & Causes, Diagnosis, Treatment, and Eating, Diet, & Nutrition), each in English and in Spanish. The page says whose words it is passing on, and what is marked “ours” is our own. The English and Spanish pages are different texts. Each English page says it was last reviewed in February 2025; each Spanish page says April 2017. This guide follows the English pages. Where a line is found only on the Spanish pages, the guide says so each time: seeing a health care professional “within 24 hours”; fever that may be the only sign under age 2; why a collection bag is not used for a baby’s sample; the list of when an ultrasound may be recommended; feeling better within one or two days; wiping from front to back; cotton underwear and loose clothes; and the line on sepsis. We do not know why the newer English pages left these out, and we did not ask. The 911 line is ours: none of the pages names 911 or gives a list of emergency signs. Numbers (8% of girls and 2% of boys by age 7; up to 3 out of 10; age 2 months; age 2 years) are the English pages’ own; the Spanish pages give a different, older figure (about 3 of every 100 children each year), which this guide does not use in English. What we left out or did not read: the name of any antibiotic or pain medicine, any amount and any number of days (the pages give none); what to do about a missed or vomited antibiotic; how much to drink (the pages say to ask); NIDDK’s separate pages on kidney infection, vesicoureteral reflux, urinary tract imaging and UTIs in adults, and its clinical trials page (not read); and anything from the two medical references the English pages cite. We called no number. It saves nothing and loads no tracking.