The diagnosis of auto-immune-mediated acquired sub-epidermal blisters: variations on a theme

Abstract

Sup-epidermal blisters which may be congenital or acquired form a heterogeneous group of conditions. Although they have variable aetiologies, there is considerable histological overlap. As a consequence, they often represent a source of considerable diagnostic difficulty. This difficulty sometimes reflects, at least in part, an attempt by the pathologist to interpret the histological features in isolation. Diagnostic dermatopathology depends upon careful clinicopathological correlation and this is of particular importance to the evaluation of bullous dermatoses. In addition to clinical and histopathological findings a routine assessment of such lesions should also include input from direct and indirect immunofluorescence investigations. On occasion ultrastructural, immunoelectron microscopic and molecular biological techniques will prove necessary before a final diagnosis can be made. In this review, the auto-immune sub-epidermal blistering diseases comprising bullous pemphigoid, cicatricial pemphigoid, herpes (pemphigoid) gestationis, inflammatory epidermolysis bullosa acquisita, linear IgA disease and bullous systemic erythematosus are considered. Dermatitis herpetiformis is also included. In addition to discussing the clinical appearance, histological features and differential diagnoses, emphasis is placed on the role of split skin immunofluorescence and Western immunoblot analysis in the evaluation of these acquired, inflammatory immunologically mediated variants.