There are few dermatologic emergencies. This is one of them known as toxic epidermal necrolysis, or TEN. Seen here is a necrotic epidermis lifting off the dermis to form a subepidermal bulla. There are several variations on this theme, which may be the result of a reaction inducing keratinocyte apoptosis as a consequence of an infection or use of a drug:

  • Erythema multiforme: there are a variety of lesions ranging from macules to papules to vesicles to bullae. The classic "target" lesion has a central vesicle surrounded by a zone of erythema and usually appears on the hands following Herpes simplex virus infection (such as "cold sores" in the mouth). This disorder is usually self-limited and classified as "minor" with <10% total body surface area involvement. More extensive "major" involvement often is seen on the face.

  • Stevens-Johnson syndrome: This is a febrile illness that is a more severe, generalized form of erythema multiforme that also involves mucus membranes and typically follows use of a drug (such as a sulfa drug or an anticonvulsant).

  • Toxic epidermal necrolysis: This is a severe febrile disorder with blistering and extensive sloughing of skin as a consequence of full thickness epidermal necrosis. A drug is usually implicated.