Erythema multiforme – low magnification
LEGEND
Acute vacuolar interface dermatitis
The stratum corneum is typically normal (not having had time to react)
Erythema multiforme – high magnification
LEGEND
- Superficial perivascular lymphocytes infiltrate with exocytosis into the epidermis
Some necrotic keratinocytes in the epidermis
Severe erythema multiforme – low magnification
LEGEND
Edema of the papillary dermis
Occasional presence of spongiosis
Acute vacuolar interface dermatitis that, if severe, can cause a subepidermal blister
Severe erythema multiforme – high magnification
LEGEND
Superficial perivascular lymphocytic infiltrate with exocytosis into the epidermis. This infiltrate is typically more abundant than in toxic epidermal necrolysis.
Variable, but non-confluent necrosis of the epidermis (some keratinocytes still retain their nuclei). This necrosis is less extensive than in toxic epidermal necrolysis.
Vacuolar interface dermatitis composed of lymphocytes
Extravasated RBCs
