Common Causes of Vaginal Itching
The three most common infectious causes of vaginal itching are vulvovaginal candidiasis (VVC), bacterial vaginosis (BV), and trichomoniasis, with VVC being the most specific for itching as a primary symptom. 1
Primary Infectious Causes
Vulvovaginal Candidiasis (Most Common for Itching)
- Vaginal itching is the most specific symptom of VVC and may be the only complaint in some cases. 2, 1
- Presents with thick, white, cottage cheese-like discharge, vaginal soreness, burning, dyspareunia, and dysuria. 3, 4
- Vaginal pH is typically ≤4.5, which distinguishes it from other causes. 1, 5
- Diagnosis confirmed by microscopy showing yeast or pseudohyphae, or by culture. 1
- Accounts for 20-25% of vaginitis cases when a cause is identified. 5
Bacterial Vaginosis
- Characterized by malodorous discharge with minimal irritation rather than prominent itching. 1, 6
- Presents with homogeneous white discharge, fishy odor (especially with KOH whiff test), and vaginal pH >4.5. 1, 6
- The absence of significant vulvar inflammation distinguishes BV from other causes. 6
- Most prevalent cause of vaginal discharge overall (40-50% of cases), but itching is not a primary feature. 2, 5
Trichomoniasis
- Presents with malodorous yellow-green frothy discharge, dysuria, and vulvar irritation with itching. 1, 6
- Vaginal pH >4.5, similar to BV. 1
- Diagnosed by visualization of motile trichomonads on wet mount or nucleic acid amplification testing. 1, 5
- Accounts for 15-20% of vaginitis cases. 5
Noninfectious Causes
Contact Dermatitis/Irritant Vaginitis
- Caused by mechanical, chemical, or allergic irritation from soaps, detergents, douches, or tight clothing. 1
- Presents with external vulvar inflammation and minimal discharge in the absence of vaginal pathogens. 2, 1
- Should be suspected when objective signs of vulvar inflammation exist with minimal discharge and no identifiable pathogens. 6
Vulvar Eczema
- Common chronic dermatosis causing vulvar pruritus. 1
- Requires restoration of epidermal barrier function and suppression of inflammation. 1, 7
Atrophic Vaginitis (Postmenopausal Women)
- Common in postmenopausal women due to estrogen deficiency. 8, 9
- Symptoms include vaginal itching, burning, dryness, irritation, and dyspareunia. 8
- Associated with decreased Lactobacillus species and increased vaginal pH. 8
- Responds to low-dose estrogen therapy with restoration of Lactobacillus-dominated microbiota. 8
Diagnostic Approach
Laboratory confirmation is essential before treatment, especially for first episodes, as symptoms alone cannot reliably distinguish between causes. 1, 5
Essential Diagnostic Steps:
- Vaginal pH testing: Normal (≤4.5) suggests candidiasis; elevated (>4.5) suggests BV or trichomoniasis. 1, 6
- Wet mount microscopy: Look for yeast/pseudohyphae (candidiasis), motile trichomonads (trichomoniasis), or clue cells (BV). 1, 6
- KOH preparation: Yeast more easily identified; fishy odor indicates BV or trichomoniasis. 2, 1
- Culture: More sensitive than microscopy for T. vaginalis and Candida species. 2
Critical Diagnostic Pitfall:
- Approximately 10-20% of women normally harbor Candida species without symptoms, so treatment must be based on both symptoms AND laboratory findings, not symptoms alone. 1, 3
- Mixed infections are common and may require combination therapy. 1
Age-Related Considerations
Reproductive Age Women:
- VVC, BV, and trichomoniasis are most common. 2, 5
- Risk factors for VVC include pregnancy, diabetes, antibiotic use, birth control pills, and immunosuppression. 4