The buccal mucosae were not involved. Annular erythematous lesions were seen on the chest, arms, thighs and legs. The epidermis is largely necrotic and contains a subepidermal vesicle. Necrotic keratinocytes are present at the dermo-epidermal junction and throughout the epidermis. The upper dermis is edematous.
Extravasated erythrocytes are present in the papillary dermis and upper dermis.
The histological features favor a diagnosis of erythema multiforme. La 6.065 high positive. Perniotic lesions with ulceration were seen on her fingertips. La 6.335 mid positive. The epidermis in areas shows some degree of basal degeneration and the upper dermis is edematous with an increase in vascularity and a patchy mild lymphohistiocytic infiltrate.