What is the diagnosis and treatment for a female patient with painful white nodules and erythema on the labia?

Diagnosis and Treatment of Painful White Nodules with Erythema on the Labia

Most Likely Diagnosis: Lichen Sclerosus

The clinical presentation of white nodules with surrounding erythema and pain on the labia is most consistent with lichen sclerosus, which should be treated with ultrapotent topical corticosteroids as first-line therapy. 1, 2

Clinical Features Supporting This Diagnosis

• Lichen sclerosus characteristically presents as porcelain-white papules and plaques with areas of ecchymosis (which may appear as surrounding erythema) affecting the interlabial sulci and labia minora 1, 3
• The main symptom is itch, often worse at night and severe enough to disturb sleep, though pain occurs when erosions or fissures are present 1, 3
• The condition may be entirely asymptomatic in some cases and discovered incidentally 1
• Lichen sclerosus has a bimodal age distribution with peaks in prepubertal girls and postmenopausal women, though it can occur at any age 1, 3

Critical Differential Diagnoses to Exclude

Infectious Causes That Must Be Ruled Out

• Vulvovaginal candidiasis can present with erythema and white discharge, though typically not as discrete white nodules 1
• Herpes simplex virus causes painful ulcerations with surrounding inflammation, not white nodules 3
• Bartholin gland infections present with swelling, erythema, and tenderness but are typically unilateral and localized to the gland 3
• Syphilis can manifest as flesh-colored papules that may be confused with other lesions 3

When Infection Is More Likely

If the patient has acute onset (days rather than weeks/months), vaginal discharge, or systemic symptoms like fever, prioritize infectious workup first 2:

• Perform vaginal pH testing (pH ≤4.5 suggests candidiasis; pH >4.5 suggests bacterial vaginosis or trichomoniasis) 2
• Obtain saline wet mount to identify clue cells or motile trichomonads 2
• Perform 10% KOH preparation to visualize yeast or pseudohyphae 2
• Consider viral culture for HSV if ulcerations are present 3

Diagnostic Approach

When to Biopsy

A biopsy is not always necessary when typical clinical features of lichen sclerosus are present, but should be strongly considered in the following situations 1:

1. Atypical features or diagnostic uncertainty
2. Young adult women in reproductive years (where lichen sclerosus is less common)
3. Persistent areas of hyperkeratosis, erosion, or erythema that fail to respond to adequate treatment
4. Any suspicion of neoplastic change with new warty or papular lesions
5. Pigmented areas to exclude melanocytic proliferation

• The biopsy should be taken from the most active sclerotic area, not from areas of scarring 1
• Good clinicopathological correlation with discussion between clinician and pathologist is vital 1

Additional Testing

• Microbiology swabs are indicated in erosive or treatment-resistant disease to exclude herpes simplex or Candida as complicating factors 1
• Autoantibody screening is useful only if clinical features suggest associated autoimmune disease 1

First-Line Treatment for Lichen Sclerosus

Initiate ultrapotent topical corticosteroid therapy with clobetasol propionate 0.05% ointment applied once daily initially, with individualized tapering based on response 2

Treatment Regimen Details

• Apply the medication to affected areas once daily during the initial treatment phase 2
• The British Association of Dermatologists recommends this as first-line treatment for lichen sclerosus 1, 2
• Taper frequency based on clinical response rather than using a fixed schedule 2

If Vulvovaginal Candidiasis Is Diagnosed Instead

For Uncomplicated Cases

Choose either fluconazole 150 mg orally as a single dose OR topical azole therapy for 1-7 days, both achieving >90% cure rates 2:

• Oral option: Fluconazole 150 mg single dose 2
• Topical option: Clotrimazole 1% cream 5g intravaginally for 7-14 days 1, 2
• Alternative topical agents include miconazole, butoconazole, and tioconazole 1

For Severe or Complicated Cases

• Severe vulvovaginitis (extensive vulvar erythema, edema, excoriation, and fissure formation) requires 7-14 days of topical azole or 150 mg of fluconazole repeated 1
• Complicated cases include recurrent disease, severe local disease, or infection in immunocompromised hosts 1

Critical Pitfalls to Avoid

• Do not dismiss ecchymosis (which may appear as erythema) in prepubertal girls as definitively indicating sexual abuse without considering lichen sclerosus 3
• Do not overlook lichen sclerosus in young patients, as it has a prepubertal peak and may be asymptomatic 2
• Do not assume a diagnosis without microscopic confirmation when considering infectious causes, as self-diagnosis is unreliable 2
• Do not use mild corticosteroids for lichen sclerosus—ultrapotent formulations like clobetasol propionate 0.05% are required 2
• Always assess for STI pathogens when genital infections are present, as multiple conditions can coexist 3, 2

Follow-Up Considerations

• Patients with vulvovaginal candidiasis should return only if symptoms persist or recur within 2 months 1
• Lichen sclerosus requires long-term monitoring due to malignancy risk (squamous cell carcinoma can develop in genital lichen sclerosus) 1
• Any persistent areas of hyperkeratosis, erosion, or new lesions warrant biopsy to exclude neoplastic change 1