What are the possible causes of chronic vaginal and perineal itching and irritation lasting months?

Chronic Vaginal and Perineal Itching and Irritation: Differential Diagnosis

Months of vaginal and perineal itching and irritation most commonly results from recurrent vulvovaginal candidiasis, lichen sclerosus, or less commonly desquamative inflammatory vaginitis, with the diagnostic approach requiring vaginal pH testing, microscopy, and consideration of inflammatory dermatoses when infectious causes are excluded. 1, 2

Primary Infectious Causes

Vulvovaginal Candidiasis (Most Common)

• Recurrent vulvovaginal candidiasis (≥4 episodes/year) presents with persistent pruritus, vulvovaginal erythema, white discharge, and normal vaginal pH (<4.5). 1, 2
• Obtain vaginal cultures before treatment to identify the Candida species, as 10-20% of recurrent cases involve C. glabrata, which is inherently resistant to fluconazole. 2
• PCR testing provides superior diagnostic performance (90% sensitivity, 94% specificity) compared to microscopy alone (58% sensitivity). 2
• Critical pitfall: Never rely on wet mount alone, as it may be negative even with active infection. 2

Trichomoniasis

• Characterized by diffuse malodorous yellow-green discharge with vulvar irritation, though some patients have minimal symptoms. 1
• Nucleic acid amplification testing is recommended for diagnosis in symptomatic women. 3
• Treatment requires oral metronidazole or tinidazole with partner therapy. 3, 4

Bacterial Vaginosis

• Presents with vaginal discharge, fishy odor, elevated pH (>4.5), and clue cells on microscopy. 1
• While typically causing discharge rather than isolated itching, it can contribute to chronic vulvar irritation. 5, 3

Primary Inflammatory/Dermatologic Causes

Lichen Sclerosus (Key Consideration for Chronic Symptoms)

• Itch is the main symptom, worse at night and severe enough to disturb sleep. 5
• Presents with porcelain-white papules and plaques, often with ecchymosis, affecting the interlabial sulci, labia minora, clitoral hood, and perineal body. 5
• Perianal lesions occur in 30% of women with lichen sclerosus. 5
• The vagina and cervix are always spared, distinguishing it from lichen planus. 5
• Some women have inactive disease with only atrophic changes but may still have active disease with hyperkeratosis requiring treatment. 5

Desquamative Inflammatory Vaginitis

• A less common inflammatory condition that should be considered when infectious causes are excluded. 6, 4
• May require treatment with topical clindamycin and steroid application. 3
• Patients should avoid sexual intercourse during initial treatment until symptoms improve. 6

Atrophic Vaginitis (Genitourinary Syndrome of Menopause)

• Consider in perimenopausal or postmenopausal women or those with hypoestrogenism. 6, 3
• Treatment involves hormonal and nonhormonal therapies, including vaginal estrogen. 6, 3

Diagnostic Algorithm

Step 1: Office-Based Testing

• Measure vaginal pH: pH <4.5 suggests candidiasis; pH >4.5 suggests bacterial vaginosis or trichomoniasis. 5, 1
• Perform wet mount microscopy: Look for yeast/pseudohyphae (candidiasis), motile trichomonads (trichomoniasis), or clue cells (bacterial vaginosis). 5, 1
• KOH preparation: Apply 10% KOH to detect amine odor (bacterial vaginosis) and visualize yeast more clearly. 5

Step 2: When Initial Testing Is Negative or Symptoms Persist

• Obtain vaginal cultures to confirm Candida species and identify non-albicans strains. 2
• Consider PCR/NAAT testing for superior sensitivity when microscopy is negative. 2, 3
• Examine for dermatologic findings: Look for porcelain-white plaques, ecchymosis, or architectural changes suggesting lichen sclerosus. 5
• Consider biopsy if inflammatory dermatoses are suspected and diagnosis is uncertain. 5, 7

Step 3: Evaluate for Contributing Factors

• Screen for diabetes, immunosuppression, HIV, and recent antibiotic use in recurrent candidiasis. 1, 2
• Assess for irritant or allergic contact dermatitis from soaps, detergents, or hygiene products. 3, 7
• Consider vulvodynia if pain predominates over itching and no pathology is identified. 4

Common Pitfalls to Avoid

• Never start empiric fluconazole maintenance without confirming species by culture, as you may be treating resistant C. glabrata. 2
• Never assume treatment failure means resistance; consider pH effects, non-albicans species, and alternative diagnoses first. 2
• Never overlook lichen sclerosus in patients with chronic nocturnal itching and normal infectious workup. 5
• Never dismiss perianal involvement as hemorrhoidal; 30% of women with lichen sclerosus have perianal lesions. 5
• Patients should be cautioned against self-medicating with over-the-counter antifungal preparations without confirmed diagnosis, as this delays appropriate care. 2

When to Reconsider the Diagnosis

If patients do not respond to initial treatment for presumed infectious vaginitis, reconsider the diagnosis and evaluate for desquamative inflammatory vaginitis, genitourinary syndrome of menopause, lichen sclerosus, or vulvodynia. 4, 7