What are the different types of vaginitis and their treatments in female patients of reproductive age?

Three Types of Vaginitis: Diagnosis and Treatment

The Three Most Common Types

The three most common types of vaginitis are bacterial vaginosis (40-50% of cases), vulvovaginal candidiasis (20-25% of cases), and trichomoniasis (15-20% of cases). 1, 2

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Bacterial Vaginosis (BV)

Pathophysiology

• BV results from replacement of normal H₂O₂-producing Lactobacillus species with high concentrations of anaerobic bacteria including Prevotella species, Mobiluncus species, Gardnerella vaginalis, and Mycoplasma hominis 1
• This represents an ecological disruption (dysbiosis) rather than infection with a single pathogen 3
• Up to 50% of women meeting clinical criteria are completely asymptomatic 1, 4

Diagnostic Criteria (Amsel Criteria - Need 3 of 4)

• Homogeneous, white, noninflammatory discharge that smoothly coats vaginal walls 1
• Vaginal pH >4.5 1, 5
• Positive whiff test (fishy odor with 10% KOH application) 1, 5
• Clue cells on microscopic saline wet mount examination 1, 5

Treatment

• First-line: Metronidazole 500 mg orally twice daily for 7 days (95% cure rate) 5, 6, 2
• Alternative regimens include intravaginal metronidazole gel or intravaginal/oral clindamycin 6, 2
• Treating male partners does NOT prevent recurrence and is not recommended 1, 5

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Vulvovaginal Candidiasis (VVC)

Pathophysiology

• Usually caused by Candida albicans, though non-albicans species (C. glabrata, C. tropicalis) can occur 7, 8
• Affects 75% of women at least once in their lifetime 6
• Recurrent VVC is defined as 4 or more episodes per year 6

Diagnostic Criteria

• Vaginal pH ≤4.5 (distinguishes from BV and trichomoniasis) 5
• Thick, white discharge with vulvovaginal pruritus and swelling 7
• Yeast or pseudohyphae visible on 10% KOH wet mount preparation 1, 7
• Culture with speciation is crucial for recurrent or complicated cases to identify non-albicans species 8, 2

Treatment

• Uncomplicated VVC: Fluconazole 150 mg orally as single dose (55% therapeutic cure rate) 5
• Topical azoles are equally efficacious and are the only option recommended during pregnancy 7, 6, 2
• Recurrent VVC: Maintenance therapy with weekly oral fluconazole for up to 6 months after initial treatment 6
• Non-albicans Candida (especially C. glabrata): Vaginal boric acid is effective first-line therapy 8

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Trichomoniasis

Pathophysiology

• Caused by the motile protozoan Trichomonas vaginalis 1
• This is a sexually transmitted infection with potentially serious sequelae 9
• Partners must be treated simultaneously to prevent reinfection 5, 9, 6

Diagnostic Criteria

• Vaginal pH >4.5 5
• Foul-smelling, frothy discharge with vaginal inflammatory changes 7
• Motile trichomonads on saline wet mount (though wet mount has high false-negative rate) 1, 7
• Nucleic acid amplification testing (NAAT) or antigen testing by immunoassay is superior to microscopy for diagnosis 6, 2

Treatment

• First-line: Metronidazole 2 grams orally as single dose (90-95% cure rate) 5, 9, 6
• Alternative: Metronidazole 500 mg twice daily for 7 days (equal efficacy) 6
• Tinidazole 2 grams orally as single dose is also highly effective (92-100% cure rates) 9
• Sexual partners MUST be treated simultaneously, even without screening 5, 9, 6
• Test of cure is not recommended after standard treatment 6
• Treatment-resistant cases may require higher-dose tinidazole 8, 6

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Critical Clinical Pearls

Diagnostic Algorithm

• Measure vaginal pH first: pH ≤4.5 suggests candidiasis; pH >4.5 indicates BV or trichomoniasis 5
• Perform saline and KOH wet mount microscopy on all patients 1
• Apply KOH and assess for fishy amine odor (whiff test positive in BV) 1, 5
• Examine saline mount for clue cells (BV) or motile trichomonads 1, 5
• Examine KOH mount for yeast/pseudohyphae (candidiasis) 1

Common Pitfalls

• Laboratory testing fails to identify the cause in a substantial minority of women 1
• Wet mount microscopy for trichomoniasis has high false-negative rates; use NAAT when available 6, 2
• Absence of symptoms does NOT exclude BV (50% are asymptomatic) 1, 4
• Culture for G. vaginalis is NOT recommended for BV diagnosis because it lacks specificity 1
• Cervical Pap tests have limited utility for BV diagnosis due to low sensitivity 1

Special Populations

• Pregnancy: Symptomatic trichomoniasis should be treated with oral metronidazole to prevent preterm birth 6
• Pregnancy: Only 7-day topical treatments should be used for BV and candidiasis 5
• HIV-infected women: Receive identical treatment regimens as non-HIV-infected women for all three conditions 5