What causes redness on the vulva and how is it treated?

Vulvar Redness: Causes and Treatment

Vulvar redness is most commonly caused by vulvovaginal candidiasis (yeast infection), bacterial vaginosis, trichomoniasis, or contact/irritant dermatitis, and should be diagnosed through vaginal pH testing and microscopic examination of discharge with treatment directed at the specific underlying cause. 1, 2

Diagnostic Approach

Initial Assessment

The diagnosis requires examining three key parameters at the bedside: 1

• Vaginal pH testing using narrow-range pH paper (normal pH ≤4.5 suggests candidiasis; pH >4.5 suggests bacterial vaginosis or trichomoniasis) 1, 2
• Microscopic examination of vaginal discharge diluted in normal saline (identifies motile trichomonads or clue cells) and 10% KOH preparation (reveals yeast forms or pseudohyphae) 1, 2
• Whiff test by applying KOH to discharge (fishy odor indicates bacterial vaginosis or trichomoniasis) 1

Common Infectious Causes

Vulvovaginal candidiasis presents with: 1, 2

• Intense vulvar itching and burning
• Vulvovaginal erythema (redness) and swelling
• Thick white discharge resembling cottage cheese
• Normal vaginal pH (≤4.5)
• Affects approximately 75% of women at least once in their lifetime

Bacterial vaginosis presents with: 1

• Homogeneous white discharge coating vaginal walls
• Vaginal pH >4.5
• Clue cells on microscopy
• Fishy odor with KOH (whiff test)
• Often minimal vulvar inflammation

Trichomoniasis presents with: 1, 2

• Diffuse malodorous yellow-green discharge
• Vulvar irritation and redness
• Vaginal pH >4.5
• Motile trichomonads on saline microscopy

Non-Infectious Causes

Contact or irritant dermatitis should be suspected when: 1, 3

• Objective signs of external vulvar inflammation are present
• Minimal vaginal discharge is noted
• Microscopy and pH testing are normal
• History suggests mechanical, chemical, or allergic irritation

Treatment Recommendations

For Uncomplicated Vulvovaginal Candidiasis

Short-course topical azole therapy (1-3 days) is the first-line treatment, with 80-90% efficacy in relieving symptoms and achieving negative cultures. 1, 2

Recommended regimens include: 1

• Oral fluconazole 150 mg as a single dose (most convenient option) 1, 4
• Clotrimazole 1% cream 5g intravaginally for 7 days (available over-the-counter) 1, 5
• Miconazole 2% cream 5g intravaginally for 7 days (available over-the-counter) 1
• Terconazole 0.8% cream 5g intravaginally for 3 days 1

Important caveats: 1

• Over-the-counter preparations should only be used by women previously diagnosed with vulvovaginal candidiasis experiencing identical symptoms
• Women whose symptoms persist after OTC treatment or recur within 2 months must seek medical evaluation to avoid delaying diagnosis of other conditions
• Oil-based creams and suppositories may weaken latex condoms and diaphragms

For Complicated or Recurrent Candidiasis

Recurrent vulvovaginal candidiasis (≥4 episodes per year) requires longer initial therapy followed by maintenance regimens. 1, 2

Initial treatment: 1, 2

• 7-14 days of topical azole therapy, OR
• Fluconazole 150 mg repeated 3 days after the first dose

Maintenance regimens (continued for 6 months): 1, 2

• Clotrimazole 500 mg vaginal suppositories once weekly, OR
• Fluconazole 100-150 mg once weekly, OR
• Ketoconazole 100 mg once daily (requires monitoring for hepatotoxicity)

Obtain vaginal cultures in recurrent cases to identify non-albicans species (particularly Candida glabrata), which are less responsive to conventional azole therapy and found in 10-20% of recurrent cases. 1

For Severe Vulvovaginal Candidiasis

Extensive vulvar erythema, edema, excoriation, and fissure formation require 7-14 days of topical azole therapy or fluconazole 150 mg repeated after 3 days. 1

Special Populations

Pregnant women: 1, 2

• Use only 7-day topical azole therapies
• Oral fluconazole is contraindicated during pregnancy

HIV-infected women: 1, 2

• Treat with the same regimens as non-HIV-infected women
• No more aggressive therapy is required

Partner Management

Treatment of male sex partners is not routinely recommended for vulvovaginal candidiasis, as it is not primarily sexually transmitted. 1 However, consider partner treatment in women with recurrent infections, and treat male partners who have symptomatic balanitis (erythematous areas on the glans with pruritus) with topical antifungal agents. 1

For Non-Infectious Causes

Contact or irritant dermatitis requires: 1, 3

• Identification and elimination of all potential irritants (soaps, detergents, feminine hygiene products, tight clothing)
• Patch testing to identify allergens in refractory cases
• Supportive care with barrier protection and gentle vulvar hygiene

Follow-Up

Patients should return only if symptoms persist or recur within 2 months of initial treatment. 1 Persistent symptoms warrant reevaluation with repeat microscopy, pH testing, and consideration of culture or biopsy to exclude other vulvar dermatologic conditions such as lichen sclerosus, lichen planus, or lichen simplex chronicus. 6, 7