Microscopic examination (Figure 3) revealed epidermal acanthosis and an epidermal invagination containing both parakeratotic crust and degenerated material. A giant cell inflammatory reaction was noted in the underlying dermis. Staining with Sel-Giemsa (Figure 4) confirmed the presence of multiple elastic fibers both within the degenerated material of the epidermal invagination and in the dermis. On the basis of the clinical and microscopic findings, a diagnosis of penicillamine-induced EPS was made. Penicillamine therapy was discontinued, and treatment with zinc acetate was initiated to control Wilson disease. The skin lesions persisted despite trials of liquid nitrogen, intralesional triamcinolone, carbon dioxide laser, and pulsed dye laser therapy. After several months of treatment with isotretinoin, however, the patient showed marked improvement. Her condition has been controlled with this regimen without recurrence for more than 2 years.
Erythematous Plaques on the Flexural Surfaces—Diagnosis. Arch Dermatol. 2005;141(11):1457-1462. doi:10.1001/archderm.141.11.1457-f