Urinary tract infection in children: diagnosis and management

Introduction

Urinary tract infections (UTIs) are among the most common bacterial infections in children, with around 8% of girls and 2% of boys experiencing at least one UTI episode by the age of seven years^​1​. Although they are rarely initially serious at onset, if left untreated they can cause complications, such as pyelonephritis or renal scarring^​2,3​. UTIs are more frequent in girls owing to anatomical factors, which include a shorter urethra, higher vaginal pH and the proximity of the urethral opening to the anus. However, during the first year of life, more boys are affected (3.7%) than girls (2.0%), with circumcised boys aged under one year being nearly ten times more likely to develop a UTI than uncircumcised boys^​4–8​.

According to Hospital Episode Statistics (HES) data, in 2023–2024, UTIs accounted for 189,756 hospital admissions and over 1.2 million NHS bed days in England, costing over £604m. Of these admissions, 8.4% involved children aged under 18 years^​9​.

This article is aimed to help pharmacists and healthcare providers understand UTIs in children. It explains what causes them, how to spot the signs, how they are treated and what can be done to help prevent them. The article also highlights the importance of using antibiotics carefully.

Bacterial causes

The majority of paediatric UTIs are caused by Gram-negative bacteria, with Escherichia coli (E. coli) accounting for around 80% of cases^​10​. Other notable pathogens include Klebsiella, Proteus mirabilis, Enterobacter and Pseudomonas aeruginosa^​2,10​. Rising rates of antibiotic resistance have led to increased reliance on broad-spectrum antibiotics, which not only carry a higher risk of complications and adverse effects but also contribute to significant financial strain on the NHS. In immunocompromised patients, UTIs caused by fungal organisms, such as Candida, can also occur^​11​.

Upper versus lower UTIs

UTIs in children are broadly classified into upper- and lower-tract infections, depending on what part of the urinary system they affect.

Lower-tract UTIs, such as cystitis, affect the bladder and urethra (i.e. urethritis) and are generally associated with symptoms, such as dysuria, frequency and urgency. These infections are mild. When treated promptly, patients rarely have long-term complications^​12​.

Upper-tract UTIs, such as pyelonephritis, involve the kidneys and are associated with symptoms such as fever, abdominal pain and nausea. These infections carry a higher risk of renal scarring — especially in younger children — and may require hospitalisation and IV antibiotics^​12​.

Risk factors

In addition to the sex differences previously mentioned, certain risk factors can significantly increase a child’s likelihood of developing a UTI, see Box^{​5–8,13​}.

Catheter-associated UTIs

Children may require catheterisation for a variety of medical reasons, including post-surgical management, urinary retention or underlying bladder issues. However, catheter use is not without risk. The longer that a catheter remains in place, the greater the likelihood that bacteria will enter the urinary tract and multiply, significantly increasing the risk of catheter-associated UTIs (CAUTIs)^​14​. Common causative organisms include E. coli, P. aeruginosa, Enterococcus and Klebsiella.

Another major contributing factor to CAUTIs is the formation of biofilms on the surface of the catheter. Biofilms are communities of bacteria that adhere to surfaces and produce a protective matrix. This matrix allows bacteria to evade the host’s immune response and resist antibiotics. Once formed, biofilms can be very difficult to eliminate without catheter removal and often lead to persistent or recurrent infections^​14​. 

Clinical signs and symptoms of CAUTIs in children include lower abdominal or suprapubic pain, changes in urine (e.g. cloudiness, foul odour), fever (≥38°C), flank pain and irritability^​15​.

Healthcare professionals play a vital role in reducing the risk of CAUTIs through strict adherence to good hygiene and infection prevention strategies^​16,17​. Important measures include: 

• Ensuring children stay properly hydrated;
• Removing catheters as soon as it is clinically appropriate;
• Ensuring all staff involved in catheter insertion and maintenance follow aseptic techniques;
• Securing the catheter properly to minimise movement and trauma to the urethra;
• Obtaining a urine sample from the catheter prior to initiating antibiotics to ensure accurate diagnosis and appropriate treatment.

Recognition

Recognising UTIs in infants and young children can be particularly difficult, as symptoms are often vague and non-specific^​18​. Infants are unable to communicate how they feel, making it essential for parents and carers to be vigilant for subtle signs. In children aged older than six months, a fever without an obvious source can indicate a UTI or other infection^​19​. For a list of the signs and symptoms of UTI to look out for, see Figure^{​8,20,21​}.

Differential diagnosis

No single sign or symptom should be taken in isolation to diagnose a UTI, as several other conditions can also present with the same non-specific symptoms. These conditions include:

• Meningitis, which may present with fever, irritability, photophobia, neck stiffness or a non-blanching rash^​22​;
• Gastroenteritis, which is often associated with diarrhoea, vomiting, abdominal pain and, sometimes, fever^​23​;
• Appendicitis, which can mimic UTI symptoms with abdominal pain, fever and urinary frequency, especially in young children;
• Vulvovaginitis (in girls), which can present with dysuria, discomfort and discharge, potentially mistaken for a UTI^​24​;
• Irritable bladder or dysfunctional voiding, which presents with frequency, urgency and incontinence but without infection;
• Sexual abuse, which should be considered in cases of recurrent UTIs, genital discomfort or unusual behavioural changes^​25​.

A thorough history, physical examination and urine testing (e.g. dipstick, microscopy and culture) are essential to ensure accurate diagnosis and avoid unnecessary antibiotic use. Physical examination in a child with suspected UTI should include an assessment of vital signs and general appearance, followed by abdominal palpation for suprapubic or flank tenderness, which may indicate cystitis or pyelonephritis. It is normally performed by a doctor or a nurse.

Diagnosis

All children with a suspected UTI should be assessed for risk of serious infection. Those identified as high-risk, such as children who are systemically unwell, showing signs of sepsis or with concerning clinical features, should be referred urgently to an appropriate specialist. In the community or primary care setting, this usually means referral to the on-call paediatric team at the nearest hospital or to emergency services if the situation dictates. This team can consist of nurses and paediatric doctors, to infectious diseases consultants. Antibiotic treatment should be started without delay, even if a urine sample has not yet been obtained.

A urine sample should be sent for microscopy and culture in the following circumstances:

• Children with fever ≥38°C without a clear source;
• Suspected pyelonephritis;
• If they remain unwell after 24 hours despite having another identified or suspected source of infection (e.g. respiratory tract infection, otitis media, skin infection).

In children aged under three months, urgent referral to a specialist is needed for the initiation of parenteral antibiotics and a urine sample should always be sent. In children aged over three months, a dipstick test should be performed and management should be based on the results. If the dipstick test is positive for leucocytes and/or nitrates, a urine sample should be sent for analysis^​20,26​.

The preferred method of urine collection is a clean catch urine sample^​27​. Potties may be used for collection if they are first cleaned thoroughly with hot soapy water. Urine collection pads are also acceptable; however, cotton wool, gauze or sanitary towels should be avoided. If non-invasive methods fail, catheterisation or suprapubic aspiration can be used^​20,28​.

Treatment

Most UTIs in children resolve on their own. When treatment is needed, a short antibiotic course is normally sufficient and when correctly managed, infections rarely lead to long-term complications. The primary goals of treatment are to relieve symptoms and prevent complications.

In children presenting with symptoms of a UTI, treatment choice should consider^​8,29​:

• Age and clinical severity;
• Past medical history;
• Local formulary;
• Previous urine culture and sensitivity results;
• A probable causative pathogen.

Where possible, a urine sample should be obtained prior to starting antibiotics. Once the culture results are available, switch to a targeted, narrow-spectrum therapy^​30​.

Antibiotic treatment by age and UTI type

The choice of antibiotic for UTIs in children should be guided by the child’s age, the type of UTI and local antimicrobial resistance (AMR) patterns. The Table below outlines recommended first-line and alternative antibiotic options, which are categorised by age group and UTI classification.

Management in infants aged under three months

According to the National Institute for Health and Care Excellence (NICE), all infants aged under three months with a suspected UTI should be referred urgently to a paediatric specialist for treatment with parenteral antibiotics, while a urine sample should be sent for urgent microscopy and culture^​19,20​.

Children aged under three months with a lower UTI

For uncomplicated lower UTIs, oral first-line options include nitrofurantoin and trimethoprim, see Table^{​12,29,31–36​}. First-line treatment may not be appropriate in patients with significant renal impairment, known allergies or local resistance patterns. If there is no improvement after at least 48 hours — or first-line treatment is not suitable — oral second-line options include amoxicillin, which has a high rate of resistance, so it should only be used if culture susceptible, and cefalexin^​31​.

Children aged under three months with an upper UTI

Oral first-line options include cefalexin and co-amoxiclav or trimethoprim, depending on cultures and sensitivities. Oral second-line options include ciprofloxacin in children aged over 16 years.

IV first-line options include amikacin, ceftriaxone, cefuroxime, gentamicin, co-amoxiclav (depending on cultures and sensitivities). For more guidance, see the NICE guideline NG109, ‘Urinary tract infection (lower): antimicrobial prescribing’^​37​.

Recurrent UTIs

Recurrent UTIs in children can occur even after proper treatment and may indicate an underlying anatomical or functional abnormality, with a diagnosis made if any of the following scenarios occur^​38​:

• Two or more episodes of UTI with acute pyelonephritis or upper UTI;
• One episode of acute pyelonephritis or upper UTI, plus one or more episodes of cystitis or lower UTI;
• Three or more episodes of cystitis or lower UTI.

Identifying recurrent UTIs is crucial, as they are associated with an increased risk of renal scarring, hypertension and chronic kidney failure, particularly in younger children^​2,10​. These cases often warrant specialist advice. Prophylactic antibiotics may be considered after optimising behavioural and hygiene measures^​38​.

Antimicrobial stewardship

Effective antimicrobial stewardship ensures antibiotics are used appropriately, helping to combat the rising threat of AMR. As part of the UK’s second five-year national action plan on AMR, the UK government has produced an initiative in 2024 that promotes the optimal use of antimicrobials to ensure safe, effective care, which aims to reduce overall antimicrobial use by 5% by 2029^​39​. A multifaceted, evidence-based and multidisciplinary approach to prescribing is essential for successful antimicrobial stewardship.

Important components include using culture and sensitivity results to guide antibiotic choice, favouring narrow-spectrum agents based on clinical guidelines, and ensuring IV antibiotics are reviewed every 24 hours and switched to oral therapy as soon as clinically appropriate. For further reading, see ‘How to evaluate the clinical appropriateness of an antimicrobial’ and ‘Switching patients from IV to oral antimicrobials’.

The role of pharmacy in antimicrobial stewardship and AMR prevention

Pharmacists and pharmacy technicians — whether based in a hospital or community setting — have a significant role in implementing good antimicrobial prescribing practices and antimicrobial stewardship in paediatrics, which include:

• Clinical review and intervention: review all antibiotic prescriptions for appropriateness, ensuring they align with local formularies and national guidelines. Antibiotics should be reviewed 48–72 hours after initiation and as soon as results from culture and sensitivities are available^​40​. Best practice principles and practical advice for structuring antimicrobial reviews and effective stewardship practices can be found in ‘How pharmacists can contribute to effective antimicrobial reviews’;
• Point-of-care support: provide pharmacy support to clinicians in choosing antibiotics, taking into account local resistance patterns, renal and hepatic function, and previous antibiotic use. See ‘Dose adjustments of antimicrobials in patients with renal impairment’ and ‘Dose adjustments of antimicrobials in patients with hepatic impairment’ for more information;
• Ensuring there is a documented antimicrobial plan: ensure that a clear clinical plan for antibiotics is documented in the patient’s notes with an appropriate duration of treatment and a planned stop or review date;
• Dose optimisation: screen prescriptions to ensure that antibiotic doses are accurately calculated based on child’s age and weight, optimising to higher dose in severe infections when needed;
• Education and counselling: provide education and training to parents and carers about antibiotic use, doses, storage, potential side effects and when to seek further medical advice;
• Audit and feedback: contribute to antimicrobial prescribing audits and provide feedback to prescribers promoting safer practices.

Prevention

• There are several measures that parents, carers and children can take to help prevent UTIs and reduce their frequency^​41​. Pharmacists and pharmacy teams should advise parents and carers to: encourage children to use the toilet regularly —ideally every three to four hours during the day and before bedtime — to avoid them holding their urine for extended periods of time;
• Ensure that they stay well hydrated by drinking plenty of fluids, especially water;
• Ensure girls are encouraged to wipe their bottoms from front to back after using the toilet to prevent the spread of bacteria to the urethra from stool;
• Avoid the use of scented soaps, bubble baths and fragranced bathing products, as these can irritate the urethra and increase the risk of developing a UTI.

Summary

Effective treatment and antimicrobial stewardship in paediatric UTIs require active collaboration among prescribers, labs, nurses and the wider pharmacy team. Pharmacists and the wider pharmacy team bridge the gap between prescribers and patients, ensuring that antimicrobial use is both rational and effective. By championing good antimicrobial stewardship, the efficacy of existing antibiotics can be preserved and children protected from the long-term consequences of AMR.