= a rare subset of chronic cutaneous LE (CCLE)
clinical:
• | erythematous , succulent, urticaria-like, non-scarring plaques with a smooth surface in sun-exposed areas (the 5 L ddx) |
• | highlights: male predominance, negative lesional DIF, and virtual absence of associated SLE disease activity |
• | ddx: Jessner’s lymphocytic infiltrate, REM, pseudolymphoma |
• | PMLE – tumid LE shows a more delayed reaction after sun exposure and healing of lesions takes longer |
• | REM – REM is mostly on chest and upper back (but difficult, as REM can be induced by sun and it responds to antimalarials) |
• | treatment: rapid and effective treatment with antimalarials (90%) |
histology:
• | perivascular and periadnexal lymphocytic infiltrate |
• | a distinct subepidermal edema |
• | moderate to copious interstitial mucin deposition (detected with colloidal iron staining) |
• | no epidermal involvement or alteration of the dermoepidermal junction (essentially only the dermal histologic changes of LE) |
• | analogy: LE --> tumid LE --> lupus profundus (EM --> Sweet’s syndrome --> e. nodosum) |
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