Toxic Epidermal Necrolysis Mimicking Linear IgA Bullous Dermatosis Without Mucosal Involvement: A Rare Case Report.

Toxic epidermal necrolysis (TEN) is defined histopathologically by full-thickness epidermal necrosis with sparse dermal inflammation. Because mucosal involvement is considered a hallmark feature, mucosal-sparing TEN is exceedingly rare and may mimic other subepidermal blistering disorders. We report an amoxicillin/clavulanate-induced TEN case presenting with tense annular vesiculobullous lesions with a "string-of-pearls" appearance clinically suggestive of linear IgA bullous dermatosis (LABD). However, histopathology showed widespread keratinocyte necrosis across all epidermal layers and minimal perivascular lymphocytic infiltration, without neutrophilic microabscesses. Two perilesional direct immunofluorescence (DIF) studies were negative for linear IgA deposition, effectively excluding LABD. This case underscores the diagnostic importance of early histopathologic and DIF evaluation of TEN cases with atypical mucosal-sparing presentations that clinically overlap with autoimmune blistering diseases.