UTI in Children

Comments from Expert Advisory Committee

UTI in children is an illness caused by infection of the lower urinary tract (cystitis), the upper urinary tract (pyelonephritis) or both.

Upper UTI (pyelonephritis) is diagnosed in children presenting with:

  • Fever ≥38⁰C and bacteriuria
  • Fever <38⁰C, loin pain/tenderness and bacteriuria

Lower UTI (cystitis) is diagnosed in children with:

  • Bacteriuria and localised symptoms including lower abdominal or suprapubic pain, dysuria, urinary frequency and urgency
  • No systemic symptoms or signs.

Symptoms/signs of a UTI in children <3 months include:

  • Fever
  • Vomiting
  • Lethargy
  • Irritability
  • Poor feeding and failure to thrive

Symptoms/signs of a UTI in children ≥3 months include:

  • As above (fever, vomiting, lethargy, irritability, poor feeding)
  • Abdominal pain, or,
  • Loin tenderness

Hospital referral:

  • Refer unwell infants under 3 months for urgent assessment
  • Refer infants <6 months to a paediatrician for follow-up.
  • Refer children <3 years post atypical or recurrent UTI for imaging


  • Have a low threshold for testing urine of unwell children who are less than 3 years
  • Perform urine dipstick in children ≥3 months with symptoms/signs of a UTI
  • To help attain a clean catch sample it may be useful to apply gentle circular stimulation of the suprapubic of the child with gauze soaked in cold water.
  • If a clean catch urine sample is not possible, a nappy pad sample is a viable alternative.
    • If there is a positive dipstick from a nappy pad try hard to get a clean catch sample.
Dipstick result on sample <4 hours old Action
Children 3 months-3 years
Leukocyte and nitrite negative

Unlikely UTI:

  • Do not send MSU unless:
    • Suspected upper UTI or pyelonephritis
    • High/medium risk of serious illness
    • Recurrent UTI
    • When clinical symptoms and dipstick results don’t correlate.
  • Do not start antibiotics
Leukocyte positive +/- nitrite positive

Probable UTI:

  • Send MSU
  • Start antibiotics
Children over 3 years
Leukocyte and nitrite positive

Probable UTI:

  • Send MSU IF:
    • Child is at intermediate/high risk of serious illness, AND/OR
    • Previous history of UTI.
  • Start antibiotics
Leukocyte negative and nitrite positive

Possible UTI:

  • Send MSU if clinically suspicious of UTI and urine sample was fresh.
  • Consider starting antibiotics pending MSU result.
Leukocyte positive and nitrite negative

Possible UTI:

  • Send MSU
  • Do not start antibiotics unless clinical evidence of UTI (leukocytes may indicate infection elsewhere).
Leukocyte negative and nitrite negative

Unlikely UTI so explore other causes

  • Do not send MSU
  • Do not start antibiotics

UTI children Leukocyte and nitrite.pdf (size 462.8 KB)

The presence of pyuria and symptoms distinguishes UTI from asymptomatic bacteriuria

Refer children <3 years post atypical or recurrent UTI for imaging.
Atypical urinary infection includes any of the following:

  • Failure to respond after 48h appropriate antibiotic treatment.
  • Poor urine flow.
  • Bladder or abdominal mass.
  • Infection with non E. coli organism.
  • Septicaemia.
  • Abnormal renal function on blood tests.

Recurrent urinary infection:

  • ≥1 episode of upper tract infection/pyelonephritis and ≥1 episode of lower tract infection OR
  • ≥2 episodes of upper tract infection/pyelonephritis OR
  •  ≥3 episodes of lower urinary tract infection or cystitis.


Choice of empirical therapy should be governed by local resistance rates where available. Patterns can vary substantially across the country.

Upper UTI

Drug Dose Duration +/- Notes
1st choice option
Cefalexin See dosing table 7-10 days
2nd choice option
Co-amoxiclav See dosing table 7-10 days

Lower UTI

Drug Dose Duration +/- Notes
1st choice option
Trimethoprim* See dosing table 3 days
Nitrofurantoin* See dosing table 3 days Nitrofurantoin liquid is an unlicensed product. Please contact community pharmacist to discuss availability.
Cefalexin See dosing table 3 days

*safe in penicillin allergy

Patient Information

Visit HPSC Information Leaflets pages for the General Public, (MRSA, CRE, etc)

We recommend patients use the website developed by HSE/ICGP/IPU partnership www.undertheweather.ie for tips on how to get better from common infections without using antibiotics, what you can do for yourself or a loved one and when to seek help.

Safe Prescribing (visit the safe prescribing page)

Reviewed March 2022

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