STI Likelihood in Dysuria Without Discharge or Lesions
No, you cannot assume low STI likelihood based solely on the absence of discharge or lesions—sexually transmitted infections remain a significant possibility in sexually active patients with dysuria, even without visible signs. 1
Key Clinical Reality
The absence of discharge or lesions does not rule out STIs in patients presenting with dysuria:
Urethritis from STIs is commonly asymptomatic or presents with minimal findings. Many urethral infections caused by Chlamydia trachomatis, Mycoplasma genitalium, Ureaplasma urealyticum, and Trichomonas vaginalis occur without visible discharge. 1
In one emergency department study, 17.3% of women with classic UTI symptoms (dysuria, frequency, urgency) and no new vaginal discharge had confirmed STIs (Neisseria gonorrhoeae or Chlamydia trachomatis). Critically, there was no significant difference in STI rates between those with positive versus negative urine cultures. 2
Sterile pyuria is highly prevalent with STIs. Among women with confirmed STIs, 74% had sterile pyuria (white blood cells in urine but negative cultures), which can easily be mistaken for a UTI. 3
Critical Diagnostic Approach
The presence or absence of vaginal discharge is the key discriminator, NOT urethral discharge or lesions:
Vaginal discharge significantly decreases UTI likelihood and should prompt evaluation for bacterial vaginosis, candidiasis, trichomoniasis, or cervicitis rather than UTI. 4
Dysuria WITHOUT vaginal discharge increases UTI probability but does not exclude STI—both conditions can coexist or present identically. 4, 5
What You Must Do
For any sexually active patient with dysuria, regardless of visible discharge or lesions:
Test for both UTI and STI pathogens. Obtain nucleic acid amplification tests (NAATs) for Chlamydia trachomatis and Neisseria gonorrhoeae from first-void urine or urethral/cervical swabs. 1
If initial STI testing is negative but urethritis or cervicitis persists, test for Mycoplasma genitalium. This pathogen causes NGU and is not detected by routine STI panels. 6
Perform urinalysis and urine culture to differentiate UTI from STI-related urethritis, but recognize that pyuria alone cannot distinguish between the two. 5, 3
Evaluate sexual history carefully. More than one sexual partner in the past year significantly predicts STI presence. 2
Treatment Implications
Do not treat empirically for UTI alone in sexually active patients without STI testing:
If you treat for presumed UTI without STI testing, you risk missing 17% of STI cases and contributing to ongoing transmission and complications like pelvic inflammatory disease. 2
The European Association of Urology guidelines emphasize that urethral infections are commonly sexually transmitted, and differentiation between gonococcal and non-gonococcal urethritis is crucial for appropriate management and partner notification. 1
Empiric dual coverage may be warranted if diagnostic testing is unavailable, treating for both UTI and common STI pathogens, particularly in high-risk populations. 1
Common Pitfall
The most dangerous assumption is equating "no visible discharge or lesions" with "low STI risk." Many STIs—particularly chlamydia and mycoplasma—cause minimal or no visible findings but still cause significant urethritis and long-term complications. 1, 6