What are the causes and treatments of vaginitis?

Causes and Treatment of Vaginitis

The three most common causes of vaginitis are bacterial vaginosis (BV), vulvovaginal candidiasis, and trichomoniasis, with bacterial vaginosis being the most prevalent cause of vaginal discharge or malodor. 1

Common Causes of Vaginitis

Bacterial Vaginosis (BV)

• Results from replacement of normal H₂O₂-producing Lactobacillus species with high concentrations of anaerobic bacteria, Gardnerella vaginalis, and Mycoplasma hominis 2, 1
• Most prevalent cause of vaginal discharge or malodor, affecting women with multiple sexual partners 1, 3
• Up to 50% of women with BV may be asymptomatic 2, 3
• Not considered exclusively sexually transmitted, although associated with having multiple sexual partners 2
• Treatment of male sexual partners has not been beneficial in preventing recurrence 2, 3

Vulvovaginal Candidiasis

• Usually caused by Candida albicans 2, 1
• Affects approximately 75% of women at least once, with 40-45% experiencing two or more episodes 1
• Not usually transmitted sexually but commonly diagnosed in women being evaluated for STDs 2
• Characterized by pruritus and erythema in the vulvovaginal area 1, 4

Trichomoniasis

• Caused by the protozoan parasite Trichomonas vaginalis 1, 4
• Sexually transmitted infection requiring treatment of both sexual partners 1, 5
• May cause a foul-smelling, frothy discharge and vaginal inflammatory changes 1, 6

Less Common Causes

• Atrophic vaginitis (due to estrogen deficiency) 4, 6
• Irritant or allergic contact vaginitis 6
• Inflammatory vaginitis 4

Diagnosis

Clinical Assessment

• Vaginitis is characterized by vaginal discharge, vulvar itching, irritation, and sometimes odor 2
• The pH of vaginal secretions should be determined using narrow-range pH paper 2
  • pH > 4.5 is typical for BV or trichomoniasis 2
  • Normal pH (4.0-4.5) is common with candidiasis 6

Microscopic Examination

• Prepare two slides from vaginal discharge 2:
  • One with saline solution to identify motile T. vaginalis or clue cells of BV
  • One with 10% potassium hydroxide (KOH) to identify yeast or pseudohyphae of Candida species

Specific Diagnostic Criteria

• Bacterial Vaginosis: Diagnosed using Amsel criteria (requires 3 of 4) 2, 3:

  • Homogeneous, white, non-inflammatory discharge that smoothly coats vaginal walls
  • Presence of clue cells on microscopic examination
  • Vaginal fluid pH > 4.5
  • Fishy odor of vaginal discharge before or after addition of 10% KOH (whiff test)

• Vulvovaginal Candidiasis: Diagnosed by 1, 4:

  • Clinical signs of vulvar inflammation
  • Vaginal discharge
  • Microscopic examination showing yeast or pseudohyphae in KOH preparation
  • Culture may be helpful for recurrent or complicated cases

• Trichomoniasis: Diagnosed by 1, 4:

  • Identification of T. vaginalis in vaginal secretion sample
  • Culture or nucleic acid amplification testing (more sensitive than microscopy)

Treatment

Bacterial Vaginosis

• First-line treatment: Metronidazole 500 mg orally twice daily for 7 days 1, 5
• Alternative regimens 1, 4:
  • Metronidazole gel intravaginally
  • Clindamycin cream intravaginally
• High recurrence rate (50-80% within a year) 3

Vulvovaginal Candidiasis

• Uncomplicated cases: Topical azole preparations or oral fluconazole 150 mg as a single dose 7, 4
• For pregnancy: Only topical azoles are recommended 1
• For recurrent cases: More extensive regimen may be required 8, 9

Trichomoniasis

• Standard treatment: Metronidazole 2g orally in a single dose 1, 5
• Treatment of sexual partners is essential to prevent reinfection 5, 6
• Alternative for resistant cases: Tinidazole 4

Atrophic Vaginitis

• Treat with topical or systemic estrogen therapy 8, 6

Special Considerations

Pregnancy

• BV during pregnancy is associated with adverse pregnancy outcomes 1, 3
• Treatment with metronidazole is recommended for symptomatic pregnant women 1
• For candidiasis during pregnancy, only topical azoles should be used 1

Recurrent Infections

• BV has a high recurrence rate and may benefit from prophylactic treatment 3
• Recurrent vulvovaginal candidiasis may require identification of non-albicans Candida species through culture 4
• Probiotics may improve cure rates when used as complementary therapy with antibiotics for BV 3

Clinical Pitfalls

• Laboratory testing fails to identify the cause of vaginitis in a substantial minority of women 2
• Symptoms alone are not reliable for diagnosis; microscopic examination is essential 8, 4
• BV is associated with increased risk for PID, preterm birth, and increased susceptibility to STIs 3