Urinary Tract Infection (UTI): Symptoms, Tests And Care

Sources checked on 9 October 2026. This guide explains the assessment and care of urinary tract infections and offers practical questions for patients and families.

Original conceptual illustration of kidneys, ureters and bladder over a clothed torso — Conceptual illustration retained from the original article. It is not a diagnostic image or a depiction of an individual’s anatomy.

What a urinary tract infection means

A urinary tract infection, or UTI, occurs when microbes cause infection somewhere in the urinary system. Bladder infection, often called cystitis, is the commonest form. Bacteria usually cause it, and infection can sometimes spread to the kidneys. Typical bladder symptoms include burning while passing urine, frequent or urgent urination despite little urine, and lower abdominal discomfort. Blood, cloudiness, or a strong smell may accompany symptoms. Anatomy, previous infections, incomplete bladder emptying, urinary obstruction, catheters, sexual activity, and menopause can affect risk. [2]

Localized and systemic infection

The European Association of Urology’s 2026 guideline distinguishes localized UTI from systemic UTI. Localized infection means bladder symptoms without evidence of systemic illness, in either sex. Fever or an unusually low temperature, shaking chills, low blood pressure, rapid heartbeat, or pain near the kidneys can point toward systemic infection, although other illnesses can cause these findings. Kidney infection and acute bacterial prostatitis are examples of systemic UTI. Risk factors such as obstruction or impaired immunity matter in either category. [3]

Why the word complicated can be confusing

IDSA’s 2025 treatment guideline also moved away from automatically labeling every male UTI complicated. Its uncomplicated category can include infection confined to the bladder in women or men; complicated UTI generally extends beyond the bladder. Symptomatic infection associated with long-term urinary devices is generally classified as complicated. These categories guide treatment rather than establish a diagnosis. Being male, having diabetes, or having a urinary abnormality still influences clinical decisions, even when those features do not automatically determine the category. Treatment selection also considers illness severity, resistance risk, and individual safety factors. [4]

When emergency care is needed

A urinary infection can occasionally trigger sepsis, a dangerous whole-body response to infection. Seek emergency help when suspected infection accompanies new breathing difficulty, confusion or disorientation, extreme pain, a weak pulse, or rapid deterioration. Clammy skin, shivering, and feeling very cold can also occur. Other infections and emergencies may look similar. Sepsis needs immediate medical assessment and treatment. Waiting for a urine culture, a home test, or a routine appointment is inappropriate when someone appears seriously ill. [1]

Kidney infection needs prompt assessment

Fever, chills, vomiting, and pain in the back or side raise concern for kidney infection, especially alongside urinary symptoms. Clinical assessment should be prompt, because dehydration, obstruction, or systemic illness can change treatment needs. NICE recommends urine culture for adults with suspected pyelonephritis and hospital referral when serious illness such as sepsis is suspected. Pregnancy, inability to keep down fluids or medicines, and higher complication risk can also justify specialist advice or hospital care. Worsening at any time, or failure to begin improving within about 48 hours after prescribed treatment starts, calls for reassessment. [5]

What urine tests can and cannot show

Diagnosis combines symptoms, relevant medical history, examination when needed, and appropriately chosen urine tests. A dipstick looks for indirect clues, including nitrites and inflammatory cells; it does not identify every infection or determine the correct antibiotic. UKHSA’s current pathway discourages dipsticks in older adults and people with urinary catheters because bacteria without infection are common. In men, a negative dipstick cannot reliably exclude UTI. Culture grows organisms and checks antibiotic susceptibility, but collection contamination and processing can affect results. A home strip, cloudy urine, or odor alone cannot settle the diagnosis, particularly when symptoms persist or the person is unwell. Vaginal irritation, discharge, or menopause-related tissue changes can suggest alternative explanations. [6]

A culture result needs clinical interpretation

Laboratory numbers do not have one universal meaning. In a study comparing midstream and catheter-collected urine from symptomatic premenopausal women, even relatively small amounts of E. coli in a midstream sample could reflect bacteria in the bladder. Other organisms in voided samples did not predict bladder findings equally well. This helps explain why a clinician may question a report, request another sample, or discuss reporting thresholds with the laboratory. The study involved a specific population and cannot supply a universal cutoff for children, pregnancy, or catheter users. Both symptoms and the specimen’s context remain essential. [7]

Symptoms that suggest another cause

Burning urination can arise from urethritis, including sexually transmitted infections, rather than bladder infection. Urethral discharge, genital irritation, a relevant sexual exposure, or cervical symptoms may lead clinicians to arrange specific testing for chlamydia, gonorrhea, or other causes. A routine urine culture is not a substitute for those tests. CDC guidance describes targeted nucleic-acid tests and assessment based on symptoms and exposure history. Identifying the actual condition matters because appropriate treatment and any partner care differ. Urinary discomfort should therefore not automatically be attributed to a familiar UTI, even after previous bladder infections. [8]

Persistent pain deserves a fresh look

Repeated bladder discomfort is not always repeated bacterial infection. Interstitial cystitis, also called bladder pain syndrome, can cause urgency, frequency, and pelvic or bladder pain that changes as the bladder fills and empties. Clinicians diagnose it by considering the history and excluding other explanations, which may include infection and other urinary disorders. A negative culture does not make a person’s pain unreal, nor does it by itself establish bladder pain syndrome. Persistent symptoms deserve reassessment, including whether antibiotics are likely to help. [9]

Care in different age groups and circumstances

Babies and children need age-specific care

Children may have painful urination, new wetting, abdominal discomfort, fever, or reduced drinking; younger babies can present less specifically. NICE recommends urgent pediatric specialist assessment for suspected UTI in babies under three months, with urgent urine microscopy and culture. Older children also need evaluation guided by age, symptoms, and how ill they appear. Clean-catch urine is preferred where practical, and urine-testing strategies vary by age. Ultrasound and other investigations are selected according to features such as age, atypical infection, and recurrence; every child does not need the same scans. Adult diagnostic shortcuts should not be applied automatically. [10]

Pediatric reflux prevention has limits

The RIVUR trial followed 607 young children with vesicoureteral reflux after a first or second febrile or symptomatic UTI. Antibiotic prophylaxis reduced recurrence over two years, with infections occurring in 39 of 302 children receiving prophylaxis and 72 of 305 receiving placebo. However, the trial did not demonstrate a significant reduction in kidney scarring, and recurrent infections were more likely to involve resistant bacteria in the prophylaxis group. These findings support carefully selected pediatric prevention decisions rather than a blanket approach. The population was predominantly girls with documented reflux, limiting extrapolation to all children with UTIs. [11]

Pregnancy changes the assessment

Urinary symptoms during pregnancy merit prompt contact with the maternity or medical team. ACOG recommends a urine culture when cystitis is suspected and, in US prenatal care, one screening culture early in pregnancy for bacteria without symptoms. Pregnancy increases the importance of identifying and treating relevant bacteriuria because kidney infection can have serious maternal and pregnancy consequences. ACOG recommends initial inpatient management for pyelonephritis during pregnancy. Antibiotic selection depends on the organism, pregnancy stage, and individual safety factors. Evidence is limited on when everyone needs repeat screening after a negative result or after successful treatment, so follow-up is individualized. [12]

Bacteria without symptoms and confusion in older adults

Asymptomatic bacteriuria means bacteria in urine without symptoms attributable to UTI, whether or not inflammatory cells are present. IDSA generally advises against treating it in nonpregnant adults, children, older care-home residents, people with diabetes, and catheter users. Important exceptions include pregnancy and planned endoscopic urologic procedures involving mucosal injury. Some highly specialized situations have evidence gaps and need specialist decisions. In an older person with confusion and bacteriuria but no urinary symptoms, fever, or circulatory instability, IDSA recommends assessment for other causes and careful observation rather than automatic antibiotics. New confusion still needs prompt medical assessment; serious systemic illness changes the urgency. [13]

Prostate involvement needs a different approach

In someone with a prostate, clinicians may need to distinguish bladder infection from acute bacterial prostatitis. The latter can cause a prolonged illness and complications such as inability to pass urine or a prostate abscess. It may develop spontaneously or after a procedure such as prostate biopsy. NICE recommends urine culture and treatment selected for the infection and its severity, with review when susceptibility results arrive. Acute urinary retention, suspected abscess, or sepsis requires hospital assessment. Lack of improvement also warrants review. [14]

UTI with a urinary catheter

A catheter changes both infection risk and test interpretation. Bacteria become increasingly common the longer a catheter remains in place, so a positive culture is not enough to diagnose catheter-associated UTI. When symptomatic infection is suspected, clinicians obtain an appropriate sample for culture and consider whether the catheter needs removal or replacement. Sampling usually uses a designated sampling port or a newly placed catheter, rather than old urine from the drainage bag. NICE emphasizes that necessary antibiotic treatment must not be delayed while organizing catheter changes. [15]

Reducing catheter-related risk

Catheter prevention focuses on using a catheter only when needed, keeping it for the shortest appropriate time, and maintaining safe drainage. CDC guidance supports hand hygiene, trained insertion and care, a closed drainage system, and unobstructed flow. Routine systemic antibiotics are not recommended simply because a person has a catheter. The care team should regularly reconsider whether it remains necessary and whether another bladder-management method fits the situation. Routine antiseptic washing or antibiotic irrigation is not a general solution. These measures reduce risk without eliminating it. [16]

Catheter prophylaxis involves a resistance tradeoff

The AnTIC randomized trial examined antibiotic prophylaxis in 404 adults who performed clean intermittent self-catheterization and experienced recurrent UTIs. Over one year, symptomatic infections requiring antibiotics were approximately 48% less frequent with prophylaxis, but resistant urinary bacteria became more common. This combination of benefit and harm is central to interpreting the study: preventing episodes can carry consequences for future treatment choices. Because the trial was unblinded and involved a specific catheter-using population, it does not justify routine prophylaxis for all catheter users. Decisions require individualized clinical assessment and attention to antimicrobial resistance. [17]

How clinicians choose treatment

Antibiotic choices depend on the likely infection site, pregnancy, kidney function, allergies, previous cultures, recent antibiotic exposure, and local resistance. For selected lower UTIs, clinician options may include nitrofurantoin, trimethoprim, fosfomycin, or pivmecillinam where appropriate and available. Those names are not interchangeable instructions: a medicine suited to bladder infection may not suit kidney or prostate infection. NICE allows clinician-managed delayed prescribing for selected nonpregnant women with lower UTI, while recommending prompt prescribing and culture for pregnant women and men. Pain relief and enough fluid to avoid dehydration may help comfort, but do not replace assessment or indicated treatment. [18]

Pivmecillinam: a specific US indication

The FDA approved Pivya, a pivmecillinam product, in April 2024. Its US label covers uncomplicated UTI in female adults with susceptible E. coli, Proteus mirabilis, or Staphylococcus saprophyticus. This is a product-specific authorization, not a statement that every UTI or every patient is eligible. The label includes restrictions related to serious beta-lactam allergy, certain carnitine disorders, and porphyria, alongside other safety considerations. Pivmecillinam’s appearance in guidelines from other countries does not make their recommendations identical to the US label. [19]

Sulopenem combination: limited treatment alternatives

Orlynvah combines sulopenem etzadroxil with probenecid. Approved in the United States in October 2024, it is labeled for uncomplicated UTI caused by specified susceptible E. coli, Klebsiella pneumoniae, or Proteus mirabilis in adult women with limited or no alternative oral antibacterial options. That limitation is central to its role. The label does not cover complicated UTI or use as oral follow-on treatment for complicated UTI, and it contains important allergy, interaction, and other safety restrictions. It is not a general treatment for kidney infection or systemic illness. [20]

Gepotidacin: check the indication carefully

Blujepa, the gepotidacin product first approved by the FDA in March 2025, has a UTI indication for female patients aged at least twelve who weigh at least forty kilograms. The infection must be uncomplicated and caused by one of the susceptible organisms named in its label. Its February 2026 labeling also contains a separate gonorrhea indication with different eligibility criteria; those criteria should not be transferred to UTI care. Heart-rhythm effects, medicine interactions, organ function, and adverse reactions require clinical review. Being a newer antibiotic does not establish that it is preferable or suitable for every patient. [21]

Safety review matters with familiar medicines

Familiar antibiotics also have important precautions. The UK medicines regulator reminds clinicians that nitrofurantoin can cause lung reactions during short or longer use and, rarely, serious liver injury. New breathing difficulty, a persistent cough, jaundice, or other concerning symptoms during treatment warrant prompt medical advice. Long-term preventive use needs appropriate monitoring, especially in older people. These risks do not mean everyone experiences them, but they help explain why repeat prescriptions need review. Repeat prescribing should account for changing health conditions and other medicines. [22]

Why broad antibiotic choices may be restricted

Fluoroquinolones, including ciprofloxacin and levofloxacin, can be useful for selected infections, but their risks affect prescribing. The MHRA’s January 2024 restrictions state that systemic fluoroquinolones should be used only when other commonly recommended antibiotics are inappropriate, for example because of resistance, contraindications, intolerance, or treatment failure. Potential adverse effects include serious tendon, nerve, muscle, joint, and mental-health problems, sometimes lasting or irreversible. The relevant balance differs between mild bladder symptoms and a serious infection with few effective alternatives. Clinicians should explain expected benefits and important warning symptoms. [23]

When infections keep returning

Recurrent UTI commonly means at least two episodes in six months or three within a year. A useful evaluation checks whether episodes actually fit bacterial infection and whether symptoms resolve between them. The AUA/CUA/SUFU guideline recommends urinalysis and culture with symptomatic episodes in women with recurrent uncomplicated cystitis, alongside a history and examination. Suspected contamination may justify repeat sampling. Persistent symptoms after infection has cleared call for consideration of other causes. Imaging and cystoscopy are not automatic for every otherwise typical recurrent episode, but unusual features or concern about an underlying problem can change the investigation plan. [24]

Choosing a prevention plan

Prevention should follow review of confirmed episodes and any treatable underlying factors. NICE’s updated recurrent-UTI guidance includes vaginal estrogen where appropriate, selected antibiotic prevention strategies, and methenamine hippurate for suitable nonpregnant people with a female urinary system after any current infection has been adequately treated. Methenamine requires specialist advice in pregnancy, children, people with a male genitourinary system, and recurrent upper or complicated lower UTI. Urine-alkalinizing products can reduce its effectiveness. Preventive treatment requires periodic review of benefit, adverse effects, and suitability. It is not a substitute for evaluating a new fever, kidney pain, or other acute illness. [25]

D-mannose lacks convincing prevention benefit

A 2024 placebo-controlled trial involving 598 women in UK primary care found no convincing preventive benefit from D-mannose. Over six months, a suspected UTI requiring medical attention occurred in 51.0% of evaluable participants receiving D-mannose and 55.7% receiving placebo, a difference compatible with chance. Symptom burden, antibiotic use, and culture-confirmed infections also showed no significant improvement. This strengthens the case against describing D-mannose as an established preventive option. The main outcome included clinically suspected infections, and findings from this primary-care population do not resolve every question about different patient groups or formulations. [26]

Cranberry evidence depends on the patient group

The November 2023 Cochrane review included 50 trials with 8,857 participants and found that cranberry products probably reduced symptomatic, culture-confirmed UTIs in women with recurrent infections. In that subgroup, the pooled relative risk was 0.74, although the confidence interval approached no effect. Benefits were also reported in children and some people undergoing bladder-related interventions. Evidence did not establish benefit in pregnant patients, institutionalized older adults, or adults with incomplete bladder emptying. Product differences, inconsistent reporting, and uncertainty about the most effective formulation limit translation into a universal recommendation; cranberry is prevention research, not treatment for an active infection. [27]

Methenamine offers an evidence-based prevention alternative

The 2022 ALTAR trial compared methenamine hippurate with antibiotic prophylaxis in 240 women with recurrent UTIs. During the treatment year, antibiotic-treated infections occurred at rates of 1.38 and 0.89 episodes per person-year, respectively. Methenamine met the trial’s predefined noninferiority criterion, which allowed a difference of one infection per person-year. This supports its role as a potential nonantibiotic preventive option within clinical care, while acknowledging that infections were numerically more frequent with methenamine. The study was unblinded, allowed treatment switching, and did not establish that both approaches are identical or suitable for every patient. [28]

Hydration evidence is strongest in women who drink little

A 2018 randomized trial studied 140 healthy premenopausal women with recurrent cystitis who ordinarily drank relatively little fluid. Participants assigned to increased water intake averaged 1.7 cystitis episodes over a year, compared with 3.2 in the control group, and required fewer antibiotic treatments. The study supports hydration as a potentially useful preventive measure for this specific population. It does not establish that additional water helps people who already drink adequately. The trial was unblinded, conducted at one center, and funded by a bottled-water company, factors that belong alongside the favorable results. [29]

Vaginal estrogen evidence concerns postmenopausal recurrence

An influential 1993 randomized trial enrolled 93 postmenopausal women with recurrent UTIs and compared vaginal estriol with placebo. Infection rates were substantially lower in the estriol group, alongside changes in vaginal acidity and restoration of lactobacilli, findings consistent with a local biological mechanism. The result helps explain why vaginal estrogen remains relevant to discussions of recurrence after menopause. However, this was a small, older study, only 60 participants completed follow-up, and adverse effects contributed to withdrawals. Its findings concern local vaginal treatment in a selected population and cannot be generalized to systemic estrogen or every postmenopausal patient. [30]

Practical support for a UTI appointment and recovery

Practical help can make assessment and recovery easier to manage. The suggestions below adapt general patient communication, medicine safety, and family support guidance to a possible UTI. They do not establish a diagnosis, replace clinical advice, or represent trials of UTI treatment.

Prepare for the visit and the sample

Before contacting the clinic, make a short timeline of what changed, when it began, and what is most troublesome now. Note how the problem affects sleep, eating, toileting, or ordinary activities, without trying to decide the diagnosis yourself. Choose two or three questions you most want answered, and mention anything that could make the proposed plan difficult. If you want another person at the appointment, agree whether their role is to listen, take notes, or help explain your concerns. Keep your own priorities at the centre of the conversation. [31]

If a urine sample is requested, ask the clinic for its collection instructions and the correct container before attempting it. Useful questions include whether the sample should be collected at home or on site, what preparation is needed, how much to collect, and where and when to deliver it. Ask about storage if prompt delivery is difficult; instructions depend on the container and test. Tell staff if mobility, vision, pain, or dexterity makes collection hard. Use the supplied equipment as directed, including any preservative instructions. If something spills or seems contaminated, explain what happened and ask whether another sample is needed. [32]

Keep medicine information usable

Keep one current medicines list that you can bring to the prescriber and pharmacist. Include prescribed medicines, nonprescription products, vitamins, supplements, and herbal preparations, with their names and the instructions you actually follow. Date the list and update it after a clinician changes the plan so that an old version does not circulate among helpers. Keep the pharmacy and prescriber contact details alongside it. If you cannot remember a medicine or understand a label, ask the pharmacist to help reconcile the record. A simple paper list is useful when a phone is unavailable. [33]

Before leaving with a prescription, confirm what the medicine is for, how to use and store it, how long the prescribed course lasts, and which problems require a call. Ask what to do if you miss a scheduled medicine or cannot keep it down; obtain instructions for your particular prescription. Record known allergies and previous medicine reactions, including what happened, and tell the clinician. Ask about interactions with everything on your medicines list. Follow the current prescribed plan, and contact the prescriber or pharmacist about uncertainties rather than improvising changes. [34]

Make the care plan understandable and accessible

Ask for explanations in everyday language, especially if a report or medicine label uses unfamiliar terms. A useful conversation covers the problem being considered, the next action, and the reason that action matters. Then describe the plan back in your own words and ask the clinician to correct anything you have misunderstood. This is a check on the explanation, not a test of intelligence. Request a short written plan you can read at home, and say if pictures, larger text, or another format would help. [35]

When language is a barrier, tell the clinic which language you prefer as soon as you book. Ask how to arrange an interpreter for the consultation, prescription discussion, and follow-up call, and request translated instructions when available. A relative who provides comfort may not be the person you want translating intimate details. Ask the service to explain its language support options, including any costs, rather than assuming you must manage alone. In the United States, HHS describes language assistance for covered health services; arrangements elsewhere differ. [36]

If cost could prevent an appointment, test, or prescription pickup, raise that concern while the plan is being made. Ask the clinic what charges to expect and whether a patient support worker can explain local assistance. In the United States, community health centres supported through HRSA are an option to investigate whether or not you have insurance, with charges linked to a sliding scale. Confirm availability and fees with the individual centre. Also explain practical barriers such as transport, childcare, or unreliable internet. [37]

Agree how results and follow-up will reach you

Before a requested test, establish who will review the result, when you should expect an explanation, and how to contact the service if it has not arrived. Put the agreed follow-up in your calendar. If a portal displays a report first, arrange the clinical explanation rather than deciding what treatment is needed from a highlighted word or number. Keep the report date, the clinician’s explanation, and the next agreed step together. When care moves between services, ask whether the relevant report has reached the next clinician. Tell staff which contact method you can reliably use, including when you cannot access a portal. [38]

Plan for school, childcare, and work

For a child who has been assessed, discuss school or childcare attendance with the clinician and check the setting’s illness policy. Consider whether the child can participate comfortably and whether staff can provide the support needed. Arrange a reachable adult and a backup pickup plan. If prescribed medicine must be given during the day, coordinate with the prescriber, pharmacist, and school health team about written instructions, required forms, and labelled containers. Ask how bathroom access and discreet help will work. These are general school-care arrangements, not a fixed exclusion period for every UTI; the individual assessment and local procedures guide the plan. [39]

For work, check the relevant absence or appointment policy and speak with the appropriate manager about the practical arrangement you need. That might mean time for a consultation, a brief change in duties, or access to a bathroom near your work area. Ask what documentation is needed and how to provide it privately. If you are accompanying someone else, explain the scheduling need and discuss cover. Acas advises checking contracts and policies and discussing individual arrangements; leave and pay depend on the circumstances and jurisdiction. [40]

Prepare for travel without interrupting care

If travel is approaching, tell the clinician where you are going and ask how the trip affects the current care plan. Check how you will receive pending results and obtain medical help at the destination. For medicines already prescribed, discuss having the necessary supply, storage during the journey, and any documentation required. Keep medicines in their original packaging and check destination rules with official authorities. Review insurance arrangements rather than assuming treatment away from home is covered. Let a trusted travel companion know what practical help you want, and keep clinic contacts accessible if your usual phone connection fails. [41]

Fit home support to the person

Ask what fluid intake is appropriate for you, especially if you already follow a restriction. There is no single drinking target that suits everyone: kidney function, other health conditions, and the clinical plan matter. A helper can make an agreed drink accessible and help track intake if the team requests it. Someone with a prescribed limit should not be pressured to exceed it because an infection is suspected. Ask whether that limit needs review during the illness. Fluids support ordinary hydration; this advice does not mean that forcing extra water cures an infection or replaces assessment and prescribed treatment. [42]

Urinary concerns can involve private questions or an examination that feels intimate. Tell the clinician if you are anxious, need a clearer explanation, or want time to speak without accompanying relatives. If an intimate examination is proposed, ask why it is needed, what will happen, and about a trained chaperone. A support person and a chaperone have different roles. Discuss what would help you feel comfortable, including privacy when changing and a way to signal that you need to pause. Families can help by asking permission before joining conversations and respecting how much the person wants to share. [43]

When several people help, agree on a small number of specific jobs: one person handles transport, another checks the written plan, and another prepares meals or covers childcare. Write down who accepted each task and when to review the arrangement. Include the person receiving care in decisions and ask what help they actually want. Keep updates factual and share health information only with people they have agreed should receive it. If relatives disagree, return to the current clinical instructions and ask the care team to clarify uncertainty. A short check-in can prevent a willing group from duplicating one task while overlooking another. [44]

Support includes listening to frustration or embarrassment without turning every conversation into advice. Ask whether the person wants company, help with one practical job, or some quiet. Offer specific help that you can reliably provide, and avoid blame or jokes about intimate symptoms. For someone who already needs ongoing care, an additional illness can stretch the household’s capacity. Caregivers also need food, rest, and opportunities to ask for support. If caring responsibilities are affecting your own health, discuss that with your healthcare professional or a local carers’ service. General emotional support complements the care plan; it does not replace it. [45]

Frequently asked questions

Does a positive urine test always mean a UTI?

No. Bacteria without relevant symptoms often do not need treatment; exceptions require clinical judgment. [13]

Can a home dipstick rule out infection?

No. Its meaning depends on symptoms and the person being assessed. [6]

When should a suspected kidney infection be assessed?

Promptly. Fever, vomiting or back or side pain can signal kidney infection. [5]

Are UTIs assessed differently during pregnancy?

Yes. Contact the maternity or medical team promptly about urinary symptoms. [12]

Can cranberry treat an active UTI?

No. Cranberry studies concern prevention, with benefits varying between groups. [27]

Should everyone with recurrent UTIs have scans?

No. Clinical history and unusual features guide whether further investigation is needed. [24]