What is the best treatment approach for a female of reproductive age presenting with vaginal itch, greyish discharge, and urinary frequency, suspected of having bacterial vaginosis (BV), yeast infection, or urinary tract infection (UTI)?

Treatment for Vaginal Itch, Greyish Discharge and Urinary Frequency

The most likely diagnosis is bacterial vaginosis (BV) based on the greyish discharge, and first-line treatment is metronidazole 500 mg orally twice daily for 7 days, while simultaneously ruling out concurrent urinary tract infection and testing for sexually transmitted infections including trichomoniasis. 1, 2

Diagnostic Approach

Immediate Clinical Assessment

• Measure vaginal pH using pH paper—a pH >4.5 strongly suggests BV or trichomoniasis rather than candidiasis 3, 1
• Perform the "whiff test" by adding 10% KOH to vaginal discharge—a fishy odor immediately after application indicates BV 3, 1
• Examine wet mount microscopy for clue cells (epithelial cells covered with adherent bacteria), which are diagnostic for BV 3, 1
• The greyish discharge described is characteristic of BV's homogeneous white-to-grey discharge that coats vaginal walls 3, 2

Essential Laboratory Testing

• Obtain nucleic acid amplification testing (NAAT) for Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis from vaginal swab, as wet mount microscopy has low sensitivity for trichomoniasis 1
• Perform urinalysis and urine culture to evaluate the urinary frequency symptom, ruling out concurrent UTI 1
• BV diagnosis requires meeting 3 of 4 Amsel criteria: homogeneous discharge, clue cells, pH >4.5, and positive whiff test 1, 2

Treatment Algorithm

First-Line Treatment for Bacterial Vaginosis

• Prescribe metronidazole 500 mg orally twice daily for 7 days (95% cure rate) 2
• Alternative regimens include metronidazole gel 0.75% intravaginally once daily for 5 days, or clindamycin cream 2% intravaginally at bedtime for 7 days 1, 2
• Metronidazole 2g single dose has lower efficacy (84% cure rate) but is useful when compliance is a concern 2

Critical Patient Counseling

• Instruct the patient to avoid all alcohol during metronidazole treatment and for 24 hours afterward due to potential disulfiram-like reaction 2
• If clindamycin cream is prescribed, warn that it is oil-based and may weaken latex condoms and diaphragms 2
• Male sex partners do not require treatment for BV, as partner treatment has not been shown to reduce recurrence rates 2

If Trichomoniasis is Confirmed

• Treat with metronidazole 2g orally as a single dose 1
• The sexual partner must be treated simultaneously with the same regimen to prevent reinfection—this is the only sexually transmitted infection where treatment recommendations vary by sex 1, 4

Managing Urinary Symptoms

• If urinalysis confirms UTI, treat according to local antibiogram and resistance patterns 1
• If urinalysis is negative, urinary frequency may be secondary to vaginal inflammation or concurrent trichomoniasis 1

Common Pitfalls to Avoid

Diagnostic Errors

• Do not rely solely on clinical appearance—molecular diagnostic tests are superior to in-office microscopy for most clinicians 4, 5
• Laboratory testing fails to identify the cause in a substantial minority of women with vaginitis symptoms 3, 2
• In a community practice study, 42% of women with vaginitis symptoms received inappropriate treatment, often due to inadequate diagnostic workup 5

Treatment Mistakes

• Do not prescribe antifungals empirically without confirming candidiasis—the greyish discharge and likely elevated pH argue against yeast infection 1, 4
• Avoid treating asymptomatic women with indeterminate results, as this exposes them to medication side effects without clear benefit 2
• Women without confirmed infections who receive empiric treatment are more likely to have recurrent visits within 90 days 5

When to Reassess

• If symptoms do not resolve after 7 days of appropriate treatment, reconsider the diagnosis 2
• Alternative diagnoses to consider include desquamative inflammatory vaginitis, genitourinary syndrome of menopause, or vulvodynia 4
• BV has a high recurrence rate—if symptoms recur, extended treatment duration with first-line agents is recommended 4