[Table/Fig-11]:

Histopathological classification

Classification	Main Histological Findings
Epidermal	In the early stage, lymphocytic infiltration and ballooning degeneration in the dermo-epidermal junction. As the disease progresses, infiltration of CD8+ lymphocytes into the epidermis, resulting in keratinocyte necrosis and subepidermal blistering. Decrease of epidermal Langerhans cells and overexpression of ICAM-1 on keratinocytes.
Dermal	Perivascular monocytic infiltration in the upper dermis; edema in the dermal papilla. It is now said that EM is always accompanied by at least some change in the epidermis.
Mixed	Epidermal changes (vacuolar degeneration of the basal layer, satellite cell necrosis); dermal changes (perivascular lymphocytic infiltration).