Vaginal Irritation: Evaluation and Treatment
Initial Diagnostic Approach
Diagnose vaginitis through vaginal pH measurement and microscopic examination of fresh vaginal secretions, as this combination reliably distinguishes between the three most common infectious causes: bacterial vaginosis (40-50% of cases), vulvovaginal candidiasis (20-25%), and trichomoniasis (15-20%). 1
Key Diagnostic Steps
- Measure vaginal pH immediately – pH >4.5 indicates bacterial vaginosis or trichomoniasis, while pH ≤4.5 suggests candidiasis 2, 3
- Perform the "whiff test" by adding 10% KOH to vaginal discharge – a fishy amine odor is positive in bacterial vaginosis and trichomoniasis 2, 3
- Examine wet mount microscopy using both saline and 10% KOH preparations to identify clue cells (bacterial vaginosis), motile trichomonads (trichomoniasis), or yeast/pseudohyphae (candidiasis) 4, 1
- Obtain nucleic acid amplification testing (NAAT) for Trichomonas vaginalis, Neisseria gonorrhoeae, and Chlamydia trachomatis from vaginal swab, since wet mount microscopy has low sensitivity for trichomoniasis 2, 5
Bacterial Vaginosis Treatment
Treat bacterial vaginosis with oral metronidazole 500 mg twice daily for 7 days as first-line therapy. 2
- Alternative regimens include metronidazole gel 0.75% intravaginally or clindamycin cream 2% intravaginally 2
- Diagnosis requires 3 of 4 Amsel criteria: homogeneous white discharge, clue cells on microscopy, vaginal pH >4.5, or positive whiff test 2, 3
- The condition represents polymicrobial dysbiosis with anaerobes (Bacteroides, Prevotella, Peptostreptococcus, Mobiluncus) replacing normal Lactobacillus flora 2, 6
- Partner treatment is NOT required for bacterial vaginosis since it is not sexually transmitted 5
- Recurrence occurs in 50-80% within one year because Lactobacillus fails to recolonize after antibiotics 6
- Treat before surgical procedures (abortion, hysterectomy) and during pregnancy due to association with adverse outcomes 2
Vulvovaginal Candidiasis Treatment
Treat uncomplicated vulvovaginal candidiasis with either topical azole formulations (butoconazole, clotrimazole, miconazole, terconazole) or oral fluconazole 150 mg as a single dose. 4
Recommended Topical Regimens
- Short-course options (3 days): Butoconazole 2% cream 5g intravaginally, Clotrimazole 100mg tablets (2 tablets), Miconazole 200mg suppository, or Terconazole 0.8% cream 4
- Single-dose options: Clotrimazole 500mg tablet or Tioconazole 6.5% ointment 5g 4
- Longer courses (7-14 days) for severe or recurrent disease: Clotrimazole 1% cream, Miconazole 2% cream, or Terconazole 0.4% cream 4
Key Clinical Points
- Diagnosis requires pruritus and vulvovaginal erythema with either microscopic visualization of yeasts/pseudohyphae or positive culture 4, 2
- Vaginal pH remains normal (≤4.5) in candidiasis, distinguishing it from other causes 4, 3
- During pregnancy, use only topical azoles – avoid oral fluconazole 2
- Culture with speciation is crucial for recurrent cases to identify non-albicans Candida species (especially C. glabrata), which may require vaginal boric acid therapy instead of standard azoles 7
- Approximately 10-20% of asymptomatic women harbor Candida – do not treat positive cultures without symptoms 4
- Partner treatment is NOT required 5
Trichomoniasis Treatment
Treat trichomoniasis with metronidazole 2g orally as a single dose, and simultaneously treat all sexual partners with the same regimen to prevent reinfection. 2, 8
- Alternative regimen: metronidazole 500mg twice daily for 7 days 4
- Classic presentation: frothy greenish discharge with vulvar itching and irritation 8
- Vaginal pH is typically >5.4 with positive whiff test 3
- NAAT testing is essential because wet mount microscopy has poor sensitivity for detecting T. vaginalis 2
- Treatment failure usually results from untreated partners – emphasize simultaneous partner treatment 8
- For metronidazole-resistant cases, use high-dose tinidazole 7
- Safe to treat during pregnancy with metronidazole 2g single dose 2
- Screen for other STIs (chlamydia, gonorrhea) since trichomoniasis is sexually transmitted 8
Atrophic Vaginitis (Postmenopausal)
Treat atrophic vaginitis in postmenopausal women with either topical or systemic estrogen therapy. 3
- Symptoms include vaginal dryness, itching, irritation, discharge, and dyspareunia 3
- Both systemic and topical estrogen treatments are equally effective 3
- Consider this diagnosis when vaginal pH is elevated but infectious causes are excluded 1
Irritant and Allergic Contact Dermatitis
Manage irritant or allergic vaginitis by identifying and eliminating the offending agent (soaps, douches, vaginal products), as these chemical irritants disrupt the protective vaginal ecosystem. 6, 1
- These noninfectious causes account for 5-10% of vaginitis cases 1
- Inflammatory vaginitis may improve with topical clindamycin and steroid application 1
- Avoid douching and harsh soaps that alter vaginal pH and microbiome 6
Critical Pitfalls to Avoid
- Do not rely on symptoms alone – bacterial vaginosis is asymptomatic in up to 50% of cases meeting diagnostic criteria 6
- Do not treat Candida based on culture alone without symptoms, as colonization is common 4
- Do not fail to treat trichomoniasis partners – this is the primary cause of treatment failure 8
- Do not use oral fluconazole during pregnancy – only topical azoles are safe 2
- Do not assume treatment failure means antibiotic resistance – consider non-albicans Candida species or untreated partners first 7