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Condition

UTI: Symptoms, Causes, and Treatment

A urinary tract infection (UTI) is a bacterial infection of the bladder or urethra — and sometimes the kidneys. The most common symptoms are a burning sensation during urination, a frequent urgent need to urinate, and cloudy or foul-smelling urine. Most uncomplicated UTIs in otherwise healthy adults clear within a few days of antibiotic treatment, often started via telehealth without an in-person visit.

Written by Gale Editorial · grounded in the cited clinical sources below · Updated 2026-06-15. How we write.

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What is a UTI?

A urinary tract infection (UTI) is a bacterial infection that can affect any part of the urinary system — the urethra, bladder, ureters, or kidneys. Most infections involve the lower tract: the bladder (cystitis) and urethra (urethritis). When bacteria reach the kidneys, the infection is called pyelonephritis and is more serious 1.

UTIs are among the most common bacterial infections worldwide. Approximately 150 million cases occur globally each year, generating roughly 10.5 million U.S. office visits and 2–3 million emergency department visits annually 3. About 40% of U.S. women develop a UTI at least once in their lifetime, and roughly 10% experience one every year 2.

Symptoms

Symptoms differ depending on which part of the urinary tract is affected.

Bladder infection (cystitis) — most common: - A burning or stinging sensation during urination - A strong, persistent urge to urinate even when little urine is passed - Cloudy, dark, or foul-smelling urine - Blood in the urine (pink or cola-colored) - Pressure or cramping in the lower abdomen or pelvis - Low-grade fever in some cases

Kidney infection (pyelonephritis) — seek care urgently: - High fever (above 101°F / 38.3°C) - Chills and shaking - Flank, side, or back pain (below the ribs) - Nausea and vomiting - Fatigue and confusion — particularly in older adults

Kidney infection symptoms overlap with bladder infection symptoms, but the fever and flank pain distinguish them. Kidney infections require prompt in-person evaluation 12.

Causes and Risk Factors

The vast majority of UTIs are caused by bacteria that enter the urethra and travel upward into the bladder. Uropathogenic *Escherichia coli* (UPEC) is the leading pathogen, followed by *Klebsiella pneumoniae*, *Staphylococcus saprophyticus*, and *Enterococcus faecalis* 3.

Why women are more affected: The female urethra is shorter than the male urethra and sits closer to the rectum, which shortens the path bacteria must travel to reach the bladder. Women develop UTIs at least four times more often than men 12.

Common risk factors include: - Sexual activity (bacteria can be introduced mechanically) - Use of spermicides or diaphragms - Menopause (reduced estrogen alters vaginal and urethral tissue) - Pregnancy (anatomical and hormonal changes increase susceptibility) - Diabetes (high glucose in urine supports bacterial growth) - Catheter use - Kidney stones or other structural abnormalities - Prior antibiotic use (disrupts the protective microbiome) - Family history of recurrent UTIs

Diagnosis

For otherwise healthy adult women with classic lower UTI symptoms — burning urination, urgency, and no fever — clinical diagnosis based on symptoms alone is often sufficient to initiate treatment. Current guidelines from the Infectious Diseases Society of America (IDSA) recognize that a urine culture is not always necessary for uncomplicated cystitis in low-risk patients 4.

When a urine test is done, the usual steps are: - Urinalysis: A rapid dipstick test that looks for nitrites (produced by common UTI bacteria), white blood cells (pyuria), and blood. - Urine culture: Identifies the specific bacteria and which antibiotics it is sensitive to. Recommended for men, pregnant women, those with recurrent infections, and anyone with symptoms that do not improve on initial treatment.

Blood tests or imaging (CT scan, ultrasound) are reserved for suspected kidney involvement, recurrent infections, or structural concerns.

Treatment

Antibiotics are the standard treatment for UTIs. The choice of antibiotic and duration depends on which part of the urinary tract is infected, local antibiotic resistance patterns, and individual patient factors 4.

First-line antibiotics for uncomplicated cystitis (IDSA/ESCMID guidelines): - Nitrofurantoin (100 mg twice daily for 5 days) — preferred initial therapy for most women due to low resistance rates and minimal impact on gut flora 4 - Trimethoprim-sulfamethoxazole (Bactrim, 1 double-strength tablet twice daily for 3 days) — appropriate when local resistance rates are below 20% 4 - Fosfomycin (single 3 g dose) — a one-time option with high patient convenience 4 - Pivmecillinam (newly FDA-approved in 2024; 3–7 days) — an emerging first-line option 2

Fluoroquinolones (ciprofloxacin, levofloxacin) are effective but are generally reserved for pyelonephritis or cases where first-line drugs are not appropriate, because overuse drives resistance.

For kidney infection (pyelonephritis): Treatment is typically 5–14 days depending on severity and antibiotic chosen. Hospitalization and intravenous antibiotics may be needed for severe cases.

How quickly do symptoms improve? Most people notice a significant reduction in burning and urgency within 24–48 hours of starting antibiotics, though the full course should be completed. If symptoms do not improve within 48–72 hours, or worsen at any point, a urine culture and in-person evaluation are warranted 1.

Telehealth and Online Treatment

Uncomplicated lower UTI is one of the clearest use cases for telehealth. A licensed clinician can evaluate symptoms via video or asynchronous questionnaire and, when the presentation is consistent with cystitis, prescribe antibiotics without an in-person visit. A 2025 study of 45,562 outpatient UTI encounters across VA medical centers found no significant difference in treatment failure rates between telehealth and in-person care for younger patients (adjusted relative risk 0.87; 95% CI 0.70–1.08), confirming clinical equivalence for uncomplicated presentations 5.

Telehealth is generally appropriate when: - The patient is an adult (not pregnant) with classic lower UTI symptoms - No fever, back pain, or chills are present - No history of recurrent, complicated, or resistant UTIs - No structural urologic abnormalities are known

In-person evaluation is needed when: - Fever, flank pain, chills, or vomiting suggest kidney involvement - Symptoms are in men, children, or pregnant women - Symptoms do not improve after 48–72 hours of antibiotic treatment - Three or more UTIs in the past 12 months (recurrent UTI workup may be warranted)

The same 2025 study found that elderly patients (65 and older) had modestly higher failure rates in telehealth settings compared to in-person care, suggesting that older adults with UTI symptoms benefit from in-person evaluation 5.

Recurrent UTIs

Recurrence is common: nearly 50% of women who have had one UTI experience another within one year 2. Recurrent UTI is defined as two or more infections in six months, or three or more in twelve months.

Strategies discussed with a clinician for recurrence prevention include: - Post-intercourse antibiotic prophylaxis — a single antibiotic dose taken after sexual activity - Low-dose daily prophylaxis — a daily antibiotic taken for three to six months - Vaginal estrogen — for postmenopausal women, restores urethral and vaginal tissue and reduces recurrence risk - Behavioral measures — adequate hydration, urinating after intercourse, and avoiding spermicides

Cranberry products are often mentioned in popular sources. Evidence from controlled trials is mixed, and no professional society currently recommends cranberry as a substitute for medical evaluation or antibiotic prophylaxis.

Common questions

How long does a UTI last without treatment?

Without antibiotics, an uncomplicated bladder infection may persist for a week or longer and can progress to a kidney infection in some cases. Most clinicians recommend against waiting on treatment for confirmed UTI symptoms. With antibiotics, burning and urgency typically improve within 24–48 hours.

Can a UTI go away on its own?

Some very mild bladder infections resolve without treatment, but this is unpredictable. Delaying treatment risks the infection spreading to the kidneys (pyelonephritis), which is more serious and harder to treat. Medical evaluation is recommended whenever UTI symptoms appear.

What does UTI urine smell like?

UTI-associated urine is often described as strong, foul, or ammonia-like. The odor results from bacterial metabolic byproducts in the urinary tract. Cloudy appearance alongside the odor is a common finding, though neither alone confirms a UTI — a urine test or clinical evaluation provides a more reliable answer.

Can men get UTIs?

Yes. UTIs are about four times less common in men than in women because the male urethra is longer, making it harder for bacteria to reach the bladder. When men do develop UTIs, especially recurrently, the cause often involves the prostate or a structural abnormality, and evaluation typically includes a urine culture and sometimes imaging.

Is a UTI sexually transmitted?

UTIs are not classified as sexually transmitted infections (STIs), but sexual activity is a known risk factor because intercourse can introduce bacteria near or into the urethra. Using condoms and urinating shortly after sex are commonly recommended measures. If urethral symptoms accompany a possible STI exposure, testing for chlamydia and gonorrhea is appropriate.

What happens if a UTI is left untreated?

An untreated lower UTI can ascend to the kidneys, causing pyelonephritis — a more serious infection with fever, flank pain, and risk of bloodstream spread (urosepsis). Kidney infections require longer antibiotic courses and sometimes hospitalization. Early treatment of cystitis prevents most of these complications.

Related conditions

Ear Infection: Symptoms, Causes, and Treatment

Specialties

Primary Care: What a PCP Treats and When to See One

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When to seek care

  • —Fever above 101°F (38.3°C) — possible kidney infection
  • —Pain or tenderness in the flank, side, or back below the ribs
  • —Chills, shaking, or sweats
  • —Nausea or vomiting with urinary symptoms
  • —Confusion or altered mental status (particularly in older adults)
  • —Symptoms in a pregnant person
  • —No improvement or worsening after 48–72 hours of antibiotics
  • —Blood in urine without other UTI symptoms

Call 911 or go to an emergency department if high fever, severe pain, or confusion accompany urinary symptoms — these may indicate a kidney infection or bloodstream spread.

General health information, not medical advice. Synthetic demonstration content.

References

  1. 1.MedlinePlus / U.S. National Library of Medicine (2024). Urinary Tract Infection in Adults. MedlinePlus Medical Encyclopedia. link ✓Symptom descriptions for cystitis and pyelonephritis, causes, diagnostic approach, treatment duration, and when to seek urgent care
  2. 2.Chu CM, Lowder JL (2023). Uncomplicated Urinary Tract Infections. StatPearls [Internet], NCBI Bookshelf (NIH). link ✓Lifetime incidence (40% of U.S. women), annual recurrence (10%), 50% recurrence within one year, first-line antibiotics and durations including pivmecillinam FDA approval 2024, sex-based risk disparity (4x higher in women)
  3. 3.Flores-Mireles AL, Walker JN, Caparon M, Hultgren SJ (2015). Urinary tract infections: epidemiology, mechanisms of infection and treatment options. Nature Reviews Microbiology. doi:10.1038/nrmicro3432 ✓Global incidence (150 million UTIs per year), U.S. office visits (10.5 million), emergency department visits (2-3 million annually), annual societal cost (~$3.5 billion), primary pathogen UPEC
  4. 4.Gupta K, Hooton TM, Naber KG, et al. (2011). International Clinical Practice Guidelines for the Treatment of Acute Uncomplicated Cystitis and Pyelonephritis in Women: A 2010 Update by the Infectious Diseases Society of America and the European Society for Microbiology and Infectious Diseases. Clinical Infectious Diseases. doi:10.1093/cid/ciq257 ✓First-line antibiotic recommendations (nitrofurantoin, TMP-SMX, fosfomycin), resistance threshold for TMP-SMX (20%), fluoroquinolone stewardship rationale, urine culture not required for uncomplicated cystitis in low-risk patients
  5. 5.Madaras-Kelly KJ, Boyd JK, Bond L (2025). The comparative effectiveness of telehealth versus primary care and collection of urine cultures on outcome in urinary tract infection. Medicine (Baltimore). doi:10.1097/MD.0000000000043172 ✓Equivalence of telehealth vs in-person care for uncomplicated UTI in younger adults (adjusted RR 0.87; 95% CI 0.70-1.08); higher failure risk for elderly patients (65+) in telehealth setting; recommendation for tailored protocols by age

https://www.gale.care/conditions/urinary-tract-infection · 5 sources. General health information, not medical advice — synthetic demonstration content.