What are the differential diagnoses, work‑up, and treatment options for a patient presenting with vaginal itching?

Vaginal Itching: Differential Diagnosis, Work-Up, and Treatment

Differential Diagnoses

Vulvovaginal candidiasis (VVC) is the most common infectious cause of vaginal itching, with itching being the most specific symptom for this condition. 1, 2

Infectious Causes (in order of likelihood):

• Vulvovaginal candidiasis (VVC): Accounts for 20-25% of vaginitis cases when a cause is identified; itching is the hallmark symptom, often accompanied by white discharge, vulvar erythema, and dyspareunia 1, 3, 2
• Bacterial vaginosis (BV): Accounts for 40-50% of vaginitis cases; characterized by malodorous discharge with minimal irritation, though itching can occur 3, 2
• Trichomoniasis: Accounts for 15-20% of cases; presents with yellow-green discharge, dysuria, and vulvar irritation alongside itching 3, 2

Non-Infectious Causes (5-10% of cases):

• Atrophic vaginitis (Genitourinary Syndrome of Menopause): Common in postmenopausal women; presents with vaginal dryness, itching, irritation, and dyspareunia 4, 5
• Contact dermatitis/Irritant vaginitis: Caused by soaps, detergents, synthetic fabrics, or hygiene products; presents with external vulvar inflammation and minimal discharge 2, 6
• Vulvar eczema: Chronic dermatosis causing persistent vulvar pruritus 2
• Allergic vaginitis: Similar presentation to irritant vaginitis but triggered by specific allergens 3

Diagnostic Work-Up

Laboratory confirmation is essential before treatment, especially for first episodes, as symptoms alone cannot reliably distinguish between causes. 2

Essential Diagnostic Steps:

1. Vaginal pH testing:

   • pH ≤4.5 suggests VVC 6, 2, 4
   • pH >4.5 indicates BV or atrophic vaginitis 6, 2
   • pH >5.4 suggests trichomoniasis 2

2. Wet mount microscopy (using both saline and 10% KOH preparations):

   • Look for yeasts or pseudohyphae (VVC) 1, 2, 4
   • Identify clue cells (BV) 2, 4
   • Visualize motile trichomonads (trichomoniasis) 2
   • Assess for absence of lactobacilli (atrophy) 4

3. Whiff test (10% KOH added to vaginal discharge):

   • Positive fishy odor indicates BV or trichomoniasis 2

4. Yeast culture (gold standard for VVC):

   • Indicated when microscopy is negative but clinical suspicion remains high 1, 4
   • Essential for identifying non-albicans Candida species in recurrent or complicated cases 1
   • Remember: 10-20% of asymptomatic women harbor Candida, so treatment requires both symptoms AND laboratory findings 2

5. Nucleic acid amplification testing (NAAT):

   • Recommended by CDC for trichomoniasis diagnosis in symptomatic or high-risk women 3
   • Newer molecular assays for VVC perform well and are increasingly available 1

Important Diagnostic Pitfalls:

• Mixed infections are common and may require combination therapy 2
• Identifying Candida by culture alone without symptoms is NOT an indication for treatment 1
• In postmenopausal women, always consider atrophic vaginitis as a primary or contributing cause 4, 5

Treatment Options

For Vulvovaginal Candidiasis (Uncomplicated):

Azole antifungals remain the treatment of choice, achieving 80-90% symptom relief and negative cultures. 1, 4

First-Line Topical Azole Regimens:

• Clotrimazole 1% cream 5g intravaginally for 7-14 days 1, 6, 4
• Miconazole 2% cream 5g intravaginally for 7 days 1, 4
• Terconazole 0.4% cream 5g intravaginally for 7 days 1, 4
• Butoconazole 2% cream 5g intravaginally for 3 days 1

Alternative Oral Therapy:

• Fluconazole 150mg single oral dose 1, 4

Important caveat: Fluconazole during pregnancy may be associated with spontaneous abortion and craniofacial/heart defects; only topical azoles should be used in pregnant women. 1

For Recurrent VVC:

• Oteseconazole (not yet commercially available) may represent a new option 1
• For non-albicans yeast infections, boric acid appears useful 1
• No evidence supports the use of probiotics 1

Newer FDA-Approved Options:

• Ibrexafungerp showed promise in clinical trials 1
• TOL-463 appeared promising in clinical trials 1

For Bacterial Vaginosis:

• Oral metronidazole 3, 7
• Intravaginal metronidazole 3, 7
• Intravaginal clindamycin 3, 7

For Trichomoniasis:

• Metronidazole 2g single oral dose (both patient and sexual partners must be treated) 1, 3, 7
• Tinidazole (alternative oral nitroimidazole) 3, 7

For Atrophic Vaginitis (Postmenopausal Women):

Vaginal estrogen is the definitive and most effective treatment for atrophic vaginitis, working by reducing vaginal atrophy, restoring lactobacilli, and lowering vaginal pH. 4

• Estradiol vaginal cream 0.01% 4
• Topical estrogen has minimal systemic absorption with no concerning safety signals regarding stroke, VTE, breast cancer, or endometrial cancer 4

Alternatives to Vaginal Estrogen:

• Vaginal DHEA (prasterone) for dyspareunia and vaginal dryness 4
• Ospemifene (oral SERM) for vaginal dryness and dyspareunia (contraindicated in estrogen-dependent cancers) 4
• Plain vaginal moisturizers (less effective than hormonal therapies) 4

Critical pitfall: Do NOT use systemic estrogen for vaginal symptoms—it does not improve vaginal health and carries cardiovascular risks. 4

For Contact Dermatitis/Irritant Vaginitis:

Discontinue all potential irritants (soaps, douches, synthetic fabrics) and use only warm water for cleansing. 6

• Implement front-to-back wiping after toileting 6
• Switch to cotton underwear changed daily 6
• Avoid tight-fitting clothing 6

When Multiple Etiologies Coexist (e.g., VVC + Atrophic Vaginitis):

Treat the acute infection first with topical azoles, then initiate vaginal estrogen therapy to address underlying atrophy and prevent recurrence. 4

Empiric Treatment Algorithm

If diagnostic testing is unavailable and VVC is suspected based on clinical presentation (itching as primary symptom, white discharge, normal pH), initiate topical azole antifungal therapy while discontinuing all potential irritants. 6

Age-Specific Considerations:

• Children <12 years: Hygiene measures are primary treatment; empiric antifungals should NOT be used without medical evaluation due to mandatory STI evaluation requirements 6
• Postmenopausal women: Consider atrophic vaginitis as primary cause; vaginal estrogen may be more appropriate than antifungals 6, 4

Follow-Up Requirements

Patients should return for evaluation if symptoms persist or recur within 2 months. 6, 4

• Persistent symptoms after empiric treatment require comprehensive diagnostic workup including culture 6
• Self-medication with OTC antifungals should only be used if the patient was previously diagnosed with VVC and experiences identical recurrent symptoms 4