What is the best course of treatment for a female of reproductive age with symptoms of vaginal itching and discharge, potentially indicative of bacterial vaginosis, yeast infections, or trichomoniasis?

Management of Vaginal Itching and Discharge in Reproductive-Age Women

The best approach is to establish an accurate diagnosis through vaginal pH testing and microscopic examination of vaginal discharge before initiating treatment, as the three most common causes—bacterial vaginosis, vulvovaginal candidiasis, and trichomoniasis—require distinctly different therapies. 1

Diagnostic Algorithm

Initial Assessment

• Measure vaginal pH using narrow-range pH paper to differentiate between conditions 2, 1:

  • pH ≤4.5 suggests vulvovaginal candidiasis (VVC)
  • pH >4.5 indicates bacterial vaginosis (BV) or trichomoniasis

• Perform wet mount microscopy by preparing two slides 2:

  • One sample diluted in normal saline to identify motile trichomonads or clue cells (BV)
  • One sample in 10% KOH to visualize yeast or pseudohyphae (candidiasis)

• Conduct the whiff test by adding KOH to vaginal discharge 2:

  • A fishy odor before or after KOH application suggests BV

Discharge Characteristics

• White, thick "cottage cheese-like" discharge with intense itching indicates VVC 3, 4
• Thin, homogeneous white discharge with fishy odor suggests BV 2
• Yellow-green, frothy, malodorous discharge indicates trichomoniasis 3, 4

Treatment by Diagnosis

Vulvovaginal Candidiasis (Most Common Cause of Itching)

For uncomplicated VVC, prescribe either oral fluconazole 150 mg as a single dose OR topical azole therapy for 3-7 days, with cure rates of 80-90%. 2, 1

First-Line Options:

• Oral fluconazole 150 mg single dose 1, 5
• Topical azoles (over-the-counter or prescription) 2, 1:
  • Clotrimazole 1% cream 5g intravaginally daily for 7-14 days
  • Clotrimazole 2% cream 5g intravaginally daily for 3 days
  • Miconazole 2% cream 5g intravaginally daily for 7 days
  • Terconazole 0.4% cream 5g intravaginally for 7 days

For Complicated VVC (recurrent, severe, non-albicans species, or immunocompromised):

• Extended therapy with topical azoles for 7-14 days 1, 3
• Fluconazole 150 mg every 72 hours for 3 doses 3
• Maintenance therapy with fluconazole 150 mg weekly for 6 months if recurrent 1, 3

Bacterial Vaginosis

Treat symptomatic BV with oral metronidazole 500 mg twice daily for 7 days. 1, 6

Treatment Options:

• Oral metronidazole 500 mg twice daily for 7 days (first-line) 1
• Metronidazole 2g orally single dose (alternative) 1
• Metronidazole gel 0.75% intravaginally 1
• Clindamycin cream 2% intravaginally 1

Critical Considerations:

• Advise patients to avoid alcohol during metronidazole treatment and for 24 hours afterward 1
• Do not treat male partners, as this has not been shown to prevent recurrence 2, 1
• Be aware that metronidazole can precipitate VVC in 12.5-30% of patients, making concurrent antifungal therapy essential if both conditions are present 3

Trichomoniasis

Treat with metronidazole 2g orally as a single dose, and simultaneously treat all sexual partners to prevent reinfection. 1, 4, 6

Treatment Options:

• Metronidazole 2g orally single dose (preferred) 1, 4
• Metronidazole 500 mg twice daily for 7 days (alternative) 1

Essential Partner Management:

• Sexual partners must be treated simultaneously to prevent reinfection 1, 4

Concurrent Infections

When both BV and candidiasis are suspected (creamy, malodorous discharge with itching), treat both conditions simultaneously. 3

• Prescribe oral metronidazole 500 mg twice daily for 7 days PLUS fluconazole 150 mg single dose 3
• Alternatively, use topical azole therapy for 7-14 days with oral metronidazole 3

Special Populations

Pregnancy

• For VVC in pregnancy, use ONLY 7-day topical azole therapy 1, 3
• Never prescribe oral fluconazole during pregnancy, as it may be associated with spontaneous abortion and congenital defects 2, 5
• Oral metronidazole can be used for BV and trichomoniasis in pregnancy 3

HIV-Infected Women

• Treat with identical regimens as HIV-negative women 2, 3
• Lower CD4+ counts are associated with increased VVC rates 2

Critical Pitfalls to Avoid

Do Not Treat Asymptomatic Findings

• Never treat based solely on microscopic findings without symptoms, as 10-20% of women normally harbor Candida in the vagina 1, 3
• Asymptomatic colonization with yeast or occasional clue cells represents normal flora variation 3

Self-Medication Cautions

• Only recommend over-the-counter antifungals for women previously diagnosed with VVC experiencing identical recurrent symptoms 1, 3
• Women whose symptoms persist after OTC treatment or who have recurrence within 2 months should seek medical evaluation 1
• Inappropriate self-treatment delays proper diagnosis of other causes 1

Treatment Completion

• Patients must complete the full treatment course even if symptoms improve, as premature discontinuation leads to treatment failure 1

Partner Treatment

• Treat partners for trichomoniasis 1, 4
• Do not routinely treat partners for BV or candidiasis, except in cases of symptomatic balanitis 1, 3

When Diagnosis Remains Unclear

• If office microscopy is negative but symptoms persist, consider culture for T. vaginalis and Candida species 2
• Nucleic acid amplification testing (NAAT) is more sensitive than microscopy for trichomoniasis 7
• Culture can identify non-albicans Candida species requiring alternative therapy 7