What is lichen sclerosus and how is it differentiated from candida (fungal infection) or bacterial infections?

Lichen Sclerosus: Definition and Differentiation from Infections

Lichen sclerosus is a chronic, lymphocyte-mediated autoimmune skin disease—not an infection—and is distinguished from candida or bacterial infections through its characteristic white atrophic appearance, chronic progressive course, and definitive diagnosis by skin biopsy. 1

What is Lichen Sclerosus?

Lichen sclerosus is a chronic inflammatory mucocutaneous disorder that predominantly affects the anogenital area, though extragenital involvement occurs in 15-20% of cases 1, 2. The disease is autoimmune in nature, not infectious, with immune dysregulation being the most accepted underlying mechanism 3.

Key Characteristics:

• Appearance: White, atrophic patches or plaques with a porcelain-white color, often with fragile, parchment-like skin 1, 4
• Location: 85-98% of cases affect the anogenital area, with a characteristic "figure-eight" pattern around the vulva and anus in females 1
• Demographics: 6-10 times more common in women than men, typically presenting in postmenopausal women (fifth to sixth decade) 1, 3
• Chronic nature: Progressive disease that can lead to scarring, labial fusion, clitoral phimosis, meatal stenosis, and urethral stricture 4

How to Differentiate from Candida (Fungal) Infections

Clinical Presentation Differences:

Candida infections present acutely with erythema, cottage cheese-like discharge, and intense itching that responds rapidly to antifungals, whereas lichen sclerosus shows chronic white atrophic changes with progressive scarring. 1, 5

• Candida: Red, inflamed tissue with white curdy discharge, acute onset, responds to antifungal treatment within days
• Lichen sclerosus: White, atrophic, sclerotic patches that progress slowly over months to years, no discharge 1, 4

Symptom Pattern:

• Candida: Acute burning, vaginal discharge, temporary symptoms that resolve with treatment
• Lichen sclerosus: Chronic intractable pruritus, soreness, dyspareunia, dysuria, and pain on defecation that persists despite antifungal treatment 1, 5

How to Differentiate from Bacterial Infections

Bacterial infections cause acute inflammation with purulent discharge, fever, and rapid symptom onset, while lichen sclerosus presents with chronic white atrophic changes without purulent discharge or systemic signs of infection. 1, 6

Key Distinguishing Features:

• Bacterial infections: Purulent discharge, acute pain, erythema, warmth, possible fever, responds to antibiotics
• Lichen sclerosus: No purulent discharge, chronic white atrophic plaques, progressive scarring, does not respond to antibiotics 1, 4

Definitive Diagnostic Approach

Biopsy is mandatory for all patients suspected of having lichen sclerosus to confirm diagnosis and rule out squamous cell carcinoma, which occurs in 4-5% of cases. 1, 3, 4

Pathognomonic Histopathological Features:

• Hyperkeratosis of the epithelium 3, 4
• Hydropic degeneration of basal cells 3, 4
• Sclerosis of subepithelial collagen 3, 4
• Dermal lymphocytic infiltration 3, 4
• Atrophic epidermis with loss of rete pegs 3, 4
• Homogenization of collagen in the upper third of dermis 3, 4

Clinical Examination Findings:

• Physical examination: Look for white atrophic patches, fissures, tears, ecchymosis, labial fusion, buried clitoris, or narrowed introitus in females; phimosis, meatal stenosis in males 1, 4
• Dermoscopic examination: Can support clinical diagnosis before biopsy 7

Critical Pitfalls to Avoid

Do not treat suspected lichen sclerosus empirically with antifungals or antibiotics—this delays diagnosis and increases malignancy risk. 1, 4

• Never assume infection: If white atrophic changes persist after treating presumed candida or bacterial infection, immediately perform biopsy 4
• Do not miss malignancy: The 4-5% risk of squamous cell carcinoma makes biopsy essential before initiating treatment 1, 3, 4
• Avoid misdiagnosing abuse: In children, lichen sclerosus signs may be confused with sexual abuse, but the chronic white atrophic pattern and biopsy findings distinguish them 1

Associated Autoimmune Conditions

Patients with lichen sclerosus have increased incidence of other autoimmune diseases, which further distinguishes it from infectious etiologies 3:

• 22% have concurrent autoimmune disease 3
• 42% have autoantibodies 3
• Common associations include diabetes, vitiligo, and alopecia 3

The presence of autoimmune comorbidities strongly supports lichen sclerosus over infectious causes. 3