[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). |