UTIs in children are treated with a course of oral antibiotics, typically lasting 2 to 14 days depending on how serious the infection is. Most kids with a straightforward bladder infection start feeling better within a day or two of starting medication, though finishing the full course is essential. The trickier part for parents is often recognizing the infection in the first place, since symptoms look very different in a baby than in an older child.
Symptoms Look Different by Age
Older kids with a UTI will usually tell you something hurts. They feel a frequent, urgent need to pee but only a small amount comes out. It may burn or sting. Their urine might smell bad, look cloudy, or have blood in it. Some develop lower belly pain, back pain, or side pain. Daytime accidents or sudden bedwetting in a child who was fully potty trained is another classic sign.
Babies and toddlers can’t tell you any of this. Instead, you’ll see nonspecific signs: unexplained fever, irritability, poor feeding, vomiting, diarrhea, or foul-smelling urine. Some infants lose weight or seem unusually tired. In rare cases, newborns develop yellowish skin or eyes. Because these symptoms overlap with so many other illnesses, UTIs in young children often get missed. If your baby is eating or drinking less than usual, isn’t producing many wet diapers, and seems unusually cranky, a urine test is worth requesting.
How Antibiotics Are Prescribed
The standard first choice for most children is trimethoprim/sulfamethoxazole, a combination antibiotic that targets the bacteria responsible for the majority of UTIs. Alternatives include amoxicillin/clavulanate and several types of cephalosporin antibiotics. Your child’s doctor will pick one based on local resistance patterns and your child’s age and history.
For a simple bladder infection (lower UTI), a short course of 2 to 4 days works as well as a longer 7 to 14 day course. Single-dose treatment is not recommended for children. If the infection has reached the kidneys, which doctors call pyelonephritis, the course extends to 10 to 14 days. Kids with structural abnormalities in the urinary tract, repeated infections, or complications like a kidney abscess may need up to 21 days.
One important reality: antibiotic resistance is rising in the bacteria that cause pediatric UTIs. E. coli, the culprit in roughly 60% of cases, now shows resistance to ampicillin about 67% of the time and resistance to trimethoprim/sulfamethoxazole about 33% of the time in recent studies. This is why a urine culture matters. It identifies the specific bacteria and shows which antibiotics will actually work, so the doctor can switch medications quickly if the first choice isn’t effective.
When a Child Needs Hospital Care
Most pediatric UTIs are treated at home with oral antibiotics. But certain situations call for hospital admission and intravenous treatment:
- All infants under 3 months old with a UTI
- Children under 2 with a fever and a UTI, since fever suggests kidney involvement
- Signs of sepsis like rapid heart rate, low blood pressure, or severe dehydration
- Inability to keep fluids or oral medication down due to vomiting
- Urinary obstruction or significant underlying kidney or urinary tract disease
In these cases, children typically receive a short course of IV antibiotics (2 to 4 days) before switching to oral medication to complete the full treatment at home.
Comfort Measures at Home
While antibiotics do the heavy lifting, a few things help your child feel better faster. Encourage plenty of water and foods with high water content like watermelon, cucumbers, and soups. Extra fluids help flush bacteria from the urinary tract. Have your child pee frequently and completely rather than holding it. A heating pad on the lower back or belly can ease discomfort. Over-the-counter pain relievers appropriate for your child’s age can also help with fever and pain.
Imaging After a UTI
After a child’s first UTI, doctors often want to check that the urinary tract is structurally normal. For children older than 2 months with an uncomplicated first infection, an ultrasound of the kidneys and bladder is typically the only imaging needed. It’s painless, involves no radiation, and can detect blockages or swelling.
Newborns get a more thorough workup because they’re at higher risk for underlying urinary abnormalities. Boys in particular may need additional testing to check for a condition called vesicoureteral reflux, where urine flows backward from the bladder toward the kidneys, and to rule out a blockage called posterior urethral valves. After age 6, routine imaging generally isn’t necessary because structural problems like reflux become much less common.
Preventing the Next Infection
Some children get UTIs repeatedly, and daily habits make a real difference in breaking that cycle. The core strategies are simple: pee every 3 hours during the day, go as soon as the urge hits, and take time on the toilet. After peeing, your child should relax, count to 10, and try to release a little more. This “double voiding” helps empty the bladder completely. Aim for 6 to 8 glasses of water a day.
Constipation is a surprisingly common contributor to recurrent UTIs in children. A full bowel puts pressure on the bladder, making it harder to empty completely and creating a breeding ground for bacteria. If your child struggles with constipation, treating it can reduce UTI recurrence on its own.
For girls, wiping front to back after using the toilet prevents bacteria from the stool from reaching the urethra. Cotton underwear allows better airflow than synthetic fabrics. Changing out of wet swimsuits promptly helps too. For all children, skip bubble baths, scented soaps in the bath, and colored or scented toilet paper, as these can irritate the urethra and make infection more likely.