Acantholysis or epidermal cellular separation is a general property of reaction of the epidermis. It may occur secondarily in many pathologic circumstances or it may be produced experimentally by cantharidin, proteolytic enzymes, sulfhydryl-splitting agents, extremes of pH, and heat.14,15 The discovery of the association of primary acantholysis with pemphigus by Civatte was a most important step in understanding pemphigus, and acantholysis has become the key to its diagnosis. The Tzanck technique, which demonstrates acantholytic cells in suspected cases of pemphigus, was a further contribution to the diagnosis of bullous diseases.16 The vigorous emphasis on primary acantholysis by later writers (Lever, Director, Rook and associates,12,13 Ormsby and Montgomery) has appeared logical in the terms of most clinical experience. This concept restricted the diagnosis of pemphigus to certain cases only, and it has seemed useful to group other cases of a severe, nonacantholytic bullous disease as a separate entity