Epidermolysis bullosa pruriginosa: a case with prominent histopathologic inflammation

Importance Epidermolysis bullosa (EB) pruriginosa is a rare variant of dystrophic EB. It may manifest late in life and is characterized by intense pruritus, resulting in a phenotype resembling acquired inflammatory dermatoses. Dermatopathology textbooks include hereditary forms of EB among the “cell-poor” list of subepidermal blistering disorders. Observations We report a case of dominant dystrophic EB pruriginosa with late-onset cutaneous manifestations. A biopsy specimen showed subepidermal blistering with prominent inflammatory cells, including numerous eosinophils. Unfamiliarity with the distinctive clinicopathologic features of EB pruriginosa led to an initial erroneous histopathologic diagnosis of an acquired autoimmune blistering disorder. Direct immunofluorescence study results were negative for immune reactants. A strong clinical suspicion of hereditary EB pruriginosa led to mutation analysis of COL7A1, which confirmed a novel, heterozygous nonglycine missense mutation. Subsequently, 2 other family members who had nail dystrophy were also correctly diagnosed as having dominant dystrophic EB, highlighting the clinical spectrum of the disorder and the intrafamilial variability in disease presentation. Conclusions and Relevance The clinical features of EB pruriginosa are becoming more widely recognized, but dermatologists, dermatopathologists, and histopathologists should be aware that inflammatory infiltrates and late presentation are potential pitfalls in correctly diagnosing this subtype of hereditary EB.