A diagnostically challenging case of pemphigus foliaceus without histologic evidence of acantholysis

Abstract

A 77-year-old woman presented with pruritic, scaly, erythematous papules and plaques on the face which then spread to involve the trunk. Over nearly two years, five skin biopsies were performed which overall suggested a subacute to chronic eczematous process without acantholysis or intraepidermal bullae. After two years of failed treatment, antibody testing via enzyme-linked immunosorbent assay demonstrated elevated anti-Desmoglein-1 IgG and normal anti-Desmoglein-3 IgG, and a skin biopsy with direct immunofluorescence revealed IgG and C3 in the intercellular space. A diagnosis of pemphigus foliaceus was made, and the patient was treated with rituximab with significant improvement. Here, we present a diagnostically challenging case of pemphigus foliaceus in which multiple biopsies failed to detect acantholysis or intraepidermal bullae – classic histological findings of this condition, thus highlighting the importance of immunologic testing in the workup of suspected autoimmune blistering disorders.