What are the clinical stages of scalp discoid lupus erythematosus, the diagnostic criteria for this condition, and the signs that indicate active versus stable disease?

Clinical Stages, Diagnostic Criteria, and Activity Assessment of Scalp Discoid Lupus Erythematosus

Clinical Stages of Scalp DLE

Scalp DLE progresses through distinct clinical stages that correlate with dermoscopic and histopathological findings, evolving from active inflammatory lesions to end-stage scarring alopecia. 1

Early/Active Stage

• Well-demarcated erythematous plaques with firmly adherent scales or crusts on the scalp 2
• Follicular keratotic plugs visible clinically and dermoscopically, representing hyperkeratosis and plugging of follicular ostia 3
• Perifollicular scaling and erythema surrounding hair follicles 4
• Intact follicular openings still present, though may show early changes 4

Progressive/Intermediate Stage

• Central atrophy beginning to develop within the discoid plaques 2
• Pigmentary changes including both hyperpigmentation at the periphery and hypopigmentation centrally 2
• Decreasing follicular openings as inflammation progresses 4
• White structureless areas appearing dermoscopically, indicating fibrosis 4

Late/Inactive Stage

• Characteristic scarring with complete loss of follicular architecture 2
• Irreversible scarring alopecia in affected areas 2
• Absent follicular openings on dermoscopic examination 4
• Fibrotic white dots and extensive white structureless areas replacing normal scalp architecture 4

Diagnostic Criteria for Scalp DLE

Diagnosis requires correlation of clinical presentation, dermoscopic features, histopathology, and direct immunofluorescence findings. 2

Clinical Diagnostic Features

• Location: Typically affects scalp, face, auricle, and lips; when extending to trunk and limbs, termed disseminated DLE 2
• Morphology: Pathognomonic discoid erythematous plaques with adherent scales, central atrophy, scarring, and pigmentary changes 2

Dermoscopic Diagnostic Criteria (Scalp)

The most diagnostically significant dermoscopic features in scalp DLE include:

• White structureless areas (present in 62% of cases) 4
• Arborizing vessels (57.8%) 4
• White scales (54.2%) 4
• Follicular keratotic plugs (47%) - highly specific when present 4
• Absent follicular openings (45.8%) indicating permanent damage 4
• Perifollicular scaling (43.9%) 4
• Pink-white background (40.4%) 4
• Speckled brown pigmentation (38%) 4
• Fibrotic white dots (33.7%) 4

Histopathological Diagnostic Criteria

Skin biopsy remains instrumental for definitive diagnosis and should demonstrate: 2

• Hyperkeratosis with follicular plugging 2
• Focal epidermal thinning with vacuolar alteration of the dermo-epidermal interface 2
• Thickening of the epidermal basement membrane 2
• Superficial and deep perivascular and periadnexal lymphocytic infiltrate, often with interstitial mucin 2

Immunopathological Diagnostic Criteria

• Direct immunofluorescence (DIF) may reveal deposits of immunoglobulins and complement at the dermo-epidermal junction (DEJ) 2
• This finding supports the diagnosis but is not universally present 2

Molecular Diagnostic Approach (Emerging)

• Gene expression analysis from plucked anagen hair follicles can differentiate CDLE from other conditions without invasive biopsy 5
• Lesional CDLE hair follicles show highly expressed genes related to apoptotic cell death, interferon signature, complement components, and CD8+ T-cell immune responses 5

Signs of Active Disease vs. Stable Disease

Distinguishing active inflammation from irreversible damage is crucial, as active disease requires immunosuppression while stable scarring does not. 6

Signs of Active/Progressive Disease

• Erythema and inflammation at lesion borders or within plaques 2, 1
• Follicular keratotic plugs present on dermoscopy - these can occur in both acute and chronic lesions but indicate ongoing follicular involvement 3
• Perifollicular scaling and erythema 4
• Arborizing vessels indicating active inflammation 4
• Progressive hair loss with new areas of involvement 2
• Presence of scales and crusts that are firmly adherent 2
• Pink-white background on dermoscopy suggesting active inflammation 4

Signs of Stable/Inactive Disease

• Absent follicular openings indicating permanent follicular destruction 4
• Fibrotic white dots and extensive white structureless areas without surrounding erythema 4
• Complete scarring with no inflammatory changes 2
• Stable pigmentary changes without progression 2
• No new lesion formation or extension of existing lesions 2
• Absence of scales in previously active areas 2

Time-Related Dermoscopic Evolution

Dermoscopic features change over time as lesions progress from active to inactive stages, with early lesions showing more follicular keratotic plugs and perifollicular changes, while late lesions demonstrate predominantly white structureless areas and absent follicular openings 1

Critical Diagnostic Pitfalls

• Do not rely on dermoscopy alone - correlation with histopathology is essential for definitive diagnosis 1
• Follicular keratotic plugs alone are not pathognomonic - they should be evaluated in conjunction with other dermoscopic and clinical features 3
• Early intervention is critical - once scarring alopecia develops, it is irreversible 2
• Repeat biopsy is recommended if lesion morphology changes or treatment fails 7