Toxic Epidermal Necrolysis (TEN), also known as Lyell's syndrome, is a life-threatening dermatological condition that is commonly induced by a reaction to medications. It is marked by the detachment of the top layer of skin (the epidermis) from the lower layers of the skin (the dermis) all over the body.

Usually, the diagnosis can be made clinically. Typically, if the clinical history is consistent with Stevens-Johnson syndrome, and the skin lesion covers greater than 30% of the body surface area, the diagnosis of TEN is appropriate.

The initial treatment is early withdrawal of culprit drugs, early referral and management in burn units or intensive care units, supportive management, and nutritional support.

TEN affects several parts of the body, but it most severely affects the mucous membranes, such as the mouth, eyes, and vagina. The severe findings of TEN are usually preceded by 1 to 2 weeks of fever. When the rash appears it may be over large and varied parts of the body, and it is often warm and appears red.

Medications are the main precipitating cause of TEN.