Histopathologic Differential Diagnosis of Subepidermal Cutaneous Blisters and Erosions at Autopsy

The histopathologic differential diagnosis of subepidermal blisters is broad and most commonly includes primary dermatologic diseases (i.e. bullous pemphigoid), secondary blistering conditions (i.e. bullous lichen planus), and drug reactions (i.e. toxic epidermal necrolysis); however, when examining blister specimens taken during autopsy, several other entities need to be added to the differential diagnosis. For one year, we biopsied cutaneous blisters and erosions found during autopsies performed at the Dallas County Medical Examiner’s Office and examined them histologically. The objective of this study was to determine the primary cause of blisters and erosions seen at autopsy, characterize them histologically in order to allow differentiation from other blistering conditions, and emphasize causes of subepidermal blisters that are often not considered in the differential diagnosis. We present eight representative cases in order to illustrate the following points. The majority of blisters and erosions examined were subepidermal and secondary to physical causes, such as burns, defibrillation, submersion, fetal maceration, and decomposition. Although primary skin conditions need to be considered when examining blisters and erosions at autopsy, the most common entities are secondary to physical causes, and these need to be included in the differential diagnosis in order to obtain an accurate diagnosis.