Discoid Lupus Erythematosus (DLE)
The most common subtype of Chronic Cutaneous Lupus Erythematosus (CCLE). It is characterized by inflammatory, scarring skin lesions that can lead to permanent alopecia and disfigurement if untreated.
Clinical Presentation
- Lesions: Erythematous, indurated plaques with adherent scaling.
- Features: Central atrophy, follicular plugging, and peripheral hyperpigmentation.
- Distribution: Predominantly sun-exposed areas (face, scalp, ears).
Diagnostic Markers
| Diagnostic Test | Key Finding |
|---|---|
| Physical Exam | Carpet Tack Sign (keratinous spikes on underside of scale). |
| Direct Immunofluorescence | “Lupus Band Test”: Granular IgG, IgM, and C3 deposition at the dermo-epidermal junction. |
High-Yield Exam Pearl:
- Systemic Risk: DLE is a localized skin disease, but approximately 5–10% of patients may develop Systemic Lupus Erythematosus (SLE).
- Treatment: Photoprotection is non-negotiable. First-line therapy includes topical or intralesional corticosteroids; refractory cases may require hydroxychloroquine.