Diagnosis of lichen planus pemphigoides in the absence of bullae on normal-appearing skin.

A case of lichen planus pemphigoides is described in which bullae and erosions affected the areas of lichen planus only. The diagnosis was confirmed by the finding of linear C3 and IgG deposition in the basement membrane zone (BMZ) of perilesional skin. Indirect immunofluorescence revealed circulating IgG anti-BMZ antibodies and a lamina lucida split was demonstrated by electron microscopy. This case challenges the clinical dogma that the occurrence of bullae on normal-appearing skin is essential for the diagnosis of lichen planus pemphigoides.