What causes pain in the vulva and labia majora, and how is it treated?

Vulvar and Labial Pain: Causes and Treatment

Primary Diagnostic Considerations

Physical examination is the foundation for evaluating vulvar and labial pain, with the most common causes being infectious vulvovaginitis, lichen sclerosus, and vulvodynia. 1

Infectious Causes

• Vulvovaginal candidiasis, bacterial vaginosis, and trichomoniasis are the three most common infectious causes of vulvar discharge and pain 1
• Vaginal pH >4.5 suggests bacterial vaginosis or trichomoniasis, while normal pH (<4.5) suggests candidiasis 1
• Perform wet mount microscopy: saline preparation identifies motile trichomonads and clue cells (bacterial vaginosis), while KOH preparation reveals yeast pseudohyphae 1
• The "whiff test" (fishy odor with KOH) indicates bacterial vaginosis 1
• External vulvar inflammation with minimal discharge and absence of vaginal pathogens suggests mechanical, chemical, allergic, or noninfectious irritation 1

Lichen Sclerosus

Lichen sclerosus should be considered when porcelain-white papules or plaques appear on the labia minora and interlabial sulci, particularly in prepubertal girls or postmenopausal women. 2

• The classic presentation includes porcelain-white papules and plaques with ecchymosis affecting the interlabial sulci, labia minora, clitoral hood, and perineal body 2
• Primary symptom is intense pruritus (worse at night), while pain and dyspareunia specifically occur when erosions or fissures develop 2
• Biopsy is the first-line diagnostic test to confirm lichen sclerosus and exclude squamous cell carcinoma 1, 2
• Document symptom duration, pattern, and any remission periods 2
• Distinguish between pruritus versus pain with erosions/fissures 2

Vulvodynia (Chronic Vulvar Pain Syndrome)

• Vulvodynia is chronic unexplained vulvar pain affecting 9-16% of women, described as burning, stinging, rawness, or irritation 3, 4, 5
• This is a diagnosis of exclusion after ruling out infectious, inflammatory, and neoplastic causes 4, 5
• Pain may be generalized (entire vulva), localized to the vestibule (vestibulodynia), or clitoris (clitorodynia) 4
• The condition involves peripheral and/or central sensitization of the nervous system 5

Treatment Algorithm

For Infectious Causes

• Bacterial vaginosis: Treat with metronidazole or clindamycin (specific regimens per CDC guidelines) 1
• Candidiasis: Antifungal therapy (topical or oral fluconazole) 1, 3
• Trichomoniasis: Metronidazole or tinidazole 1

For Lichen Sclerosus

Ultrapotent topical corticosteroid clobetasol propionate ointment is the accepted first-line treatment. 1, 2

• Apply clobetasol propionate once nightly for 4 weeks, then alternate nights for 4 weeks, then twice weekly for the final month 2
• Long-term surveillance is mandatory due to 4-5% malignancy risk (squamous cell carcinoma) 1
• For introital narrowing causing dyspareunia: surgery using posterior vaginal wall reconstruction, followed by topical steroids with vaginal dilators postoperatively to prevent readhesion 1, 2
• For pseudocyst of clitoris (painful keratinous debris under clitoral hood adhesions): division of adhesions or circumcision if symptomatic 1

For Vulvodynia/Neuropathic Pain

Neuropathic vulvar pain does not respond to topical corticosteroids and requires specific neuropathic pain management. 1, 2

• Try lidocaine 5% ointment for localized relief 2
• Tricyclic antidepressants (amitriptyline) for chronic neuropathic pain 2, 3
• Calcium citrate supplementation 3
• Pelvic floor physical therapy with biofeedback 3, 6
• Psychological approaches and multidisciplinary pain management 4, 6, 5

Imaging When Indicated

• Transvaginal ultrasound is the initial imaging study of choice for pelvic pain when physical examination is abnormal or inconclusive 1
• Combined transabdominal and transvaginal approach with Doppler provides optimal evaluation 1
• MRI pelvis with gadolinium is the problem-solving examination when ultrasound is nondiagnostic or for surgical planning 1
• Translabial or transvaginal ultrasound evaluates perineal and vaginal cysts 1

Critical Pitfalls to Avoid

• Do not assume all vulvar pain is infectious—failure to consider lichen sclerosus or vulvodynia delays appropriate treatment 1, 2
• Do not use topical corticosteroids for vulvodynia—this represents neuropathic pain requiring different management 1, 2
• Do not neglect STI testing (gonorrhea, chlamydia, HSV, syphilis) when ulcerations, papules, or gland involvement is present 2
• Ensure patient compliance with topical corticosteroids—patients may be alarmed by package warnings against anogenital use; verify adequate application technique, amount, and correct site 1
• Biopsy any treatment-resistant lesions to exclude squamous cell carcinoma, especially in long-standing lichen sclerosus 1, 2
• Address psychosexual dysfunction—chronic genital conditions significantly impact quality of life and sexual function, requiring referral to appropriate specialists 1, 5