What is the recommended evaluation and management for secondary scarring alopecia?

Secondary Scarring Alopecia: Evaluation and Management

Overview and Classification

Secondary scarring alopecia results from nonfollicular scalp conditions that damage the dermis and secondarily destroy hair follicles, requiring identification and treatment of the underlying cause to prevent permanent hair loss. 1

Secondary scarring alopecia differs fundamentally from primary forms—the hair follicle is not the primary target but rather becomes collateral damage from other pathologic processes affecting the scalp. 2, 1

Common Underlying Causes

Secondary scarring alopecia can result from:

• Trauma: Burns, radiation injury, mechanical trauma 1
• Inflammatory conditions: Morphea (localized scleroderma), sarcoidosis 1, 3
• Infections: Lupus vulgaris (cutaneous tuberculosis), severe bacterial or fungal infections 1, 3
• Neoplasms: Primary or metastatic scalp tumors 1
• Congenital defects: Aplasia cutis congenita (congenital absence of skin) 1, 3

Diagnostic Evaluation

Clinical Assessment

Obtain a detailed history focusing on the time course of hair loss, preceding trauma or infection, systemic symptoms, and associated scalp changes including inflammation, scaling, or nodules. 4

Key clinical features to document:

• Completeness and pattern of hair loss: Secondary scarring typically shows irregular patterns corresponding to the underlying condition 4
• Scalp symptoms: Pain, pruritus, burning sensations 4
• Signs of inflammation or infection: Erythema, pustules, crusting, nodules 4
• Associated findings: Skin changes elsewhere (morphea plaques, sarcoid lesions), systemic symptoms 1

Trichoscopy

Use trichoscopy as a non-invasive bedside tool to identify patterns, guide biopsy site selection, and distinguish secondary scarring from primary cicatricial alopecias. 4, 5

Trichoscopy in secondary scarring alopecia typically lacks the specific follicular patterns seen in primary forms (yellow dots, exclamation mark hairs) and instead shows features of the underlying condition. 5

Laboratory Testing

Order targeted laboratory tests based on clinical suspicion of the underlying condition:

• Fungal culture: When tinea capitis or deep fungal infection is suspected 4
• Bacterial culture: For suspected bacterial folliculitis or abscess 4
• Lupus serology (ANA, anti-dsDNA, complement levels): When systemic lupus or cutaneous lupus is in the differential 4
• Syphilis serology: When secondary syphilis is suspected 4
• TSH and thyroid antibodies: To exclude thyroid disease 4
• Serum ferritin, vitamin D, zinc: To assess nutritional status, though these are less directly relevant to secondary causes 4

Histopathology

Perform scalp biopsy early in the disease course for definitive diagnosis, as this is essential to identify the underlying condition causing secondary follicular destruction. 4, 6

The biopsy should include:

• Multiple stains: Hematoxylin and eosin (H&E), periodic acid-Schiff (PAS) for fungi, Weigert stain for elastic fibers 4
• Adequate depth: Must include reticular dermis to identify secondary causes 2
• Site selection: Use trichoscopy to guide biopsy to areas showing active disease 4, 5

Histopathology in secondary scarring alopecia shows primary dermal pathology (inflammation, fibrosis, granulomas, neoplastic infiltrate) with secondary follicular destruction, distinguishing it from primary scarring alopecias where follicular inflammation is the primary event. 2, 3

Management Approach

Treatment Principles

Initiate early aggressive treatment directed at the underlying condition to prevent further follicular destruction, as established scarring cannot be reversed. 4, 6

The management strategy depends entirely on identifying and treating the specific underlying cause:

• Morphea: Topical or intralesional corticosteroids, systemic immunosuppression for active disease 1
• Infections: Appropriate antimicrobial therapy (antifungals for tinea, antibiotics for bacterial infections, antituberculous therapy for lupus vulgaris) 1, 3
• Sarcoidosis: Intralesional or systemic corticosteroids, immunosuppressive agents 1, 3
• Neoplasms: Surgical excision, radiation, or chemotherapy as appropriate 1

Monitoring and Follow-up

Use trichoscopy with photographic documentation at each visit to objectively evaluate treatment response and disease progression. 4, 5

Monitor for:

• Signs of disease activity: New areas of hair loss, persistent inflammation 4
• Adverse effects: Of systemic treatments when used 4
• Psychological impact: Provide support as needed, as permanent hair loss causes significant distress 4

Surgical Options

Consider hair transplantation or surgical scar revision only after the underlying condition is completely inactive and stable for at least 12-24 months. 1

Surgery is appropriate only for localized scars from resolved conditions (trauma, burns, resolved infections), not for ongoing inflammatory or neoplastic processes. 1

Critical Pitfalls to Avoid

• Delaying biopsy: Detection of the underlying disorder may be difficult in end-stage lesions, making early biopsy crucial 1
• Treating empirically without diagnosis: Secondary scarring requires specific treatment of the underlying cause, not generic anti-inflammatory therapy 6, 1
• Missing systemic disease: Always consider whether scalp involvement represents localized or systemic disease (lupus, sarcoidosis) 1, 3
• Attempting hair restoration prematurely: Transplantation into active inflammatory or neoplastic tissue will fail and may worsen the condition 1