HISTOPATHOLOGY OF EXPERIMENTAL ECZEMA (ALLERGIC CONTACT-TYPE ECZEMATOUS DERMATITIS) IN MAN* A STUDY BY THE TECHNICS OF SILVER IMPREGNATIONS OF Rio HORTEGA WITH SPECIAL REFERENCE TO THE EARLY MicRoscoPlclc LEsIoNs

Towards the end of the past century, IJnna and Besnier published their studies on histopathology of eczema (now often called "allergic eczematous contact-type dermatitis" a name coined by Sulzberger to distinguish this entity from atopic dermatitis and circumscribed lichen simplex). These descriptions are now classics and have been extensively quoted in most well-known textbooks of dermatology. These authors considered that intercellular epidermic edema—described as "status spongoides" (IJnna) and "spongiosis" (Besnier)—was the fundamental lesion in eczema. On the basis of this spongiosis the vesicles would be formed by the confluence of those small foci of edema. Gans (1), Kreibich (2), MacLeod (3) and MacCarthy (4), among others, have developed this classic description in their well known books.' In 1925, Civatte (5) in France, published a revision on the subject and sustained that in eczema, a primary microscopic vesicle ("vésiculette primordiale") appeared in the stratum mucosum before the spongiosis. Spongiosis does not always follow the primary lesion. The "vésiculette primordiale" is formed by lysis of two or three malpighian cells, through cytoplasmic alteration. This primary lesion is frequently followed by spongiosis which tends to enlarge the cavity by the current of serum that comes from the papillary body. This process gives place to a larger cavity that occupies the greater depth of the prickle cell layer. Therefore, according to Civatte, the process appears to be originally of intracellular nature, followed by intercellular edema. In spite of the lack of confirmatory reports abroad, Civatte insisted in his findings in 1936 (6) and 1937 (7)2 In 1937, Darier supported Civatte's opinion (8). Percival and coworkers (9), without mentioning Civatte or discussing the "alteration cavitaire" describe the process of eczema as follows: "multiple localised foci of epidermal necrosis are produced with, or as a result of, the allergic process" mentioning "liquefied epidermal cells in a commencing vesicle". Sachs, Miller and Gray (10), in 1944, studied the histopathology of eczematoid dermatosis in their typical aspects but omitted the early alterations.