Toxic epidermal necrolysis [Lyell]

This code represents Toxic Epidermal Necrolysis (TEN), a severe, life-threatening mucocutaneous reaction characterized by widespread epidermal detachment, often triggered by medications. It involves extensive blistering and sloughing of the skin and mucous membranes, resembling a severe burn.

Use this code for patients diagnosed with TEN, also known as Lyell's syndrome, based on clinical presentation and histological findings. Documentation should clearly describe the extent of epidermal detachment, the presence of Nikolsky's sign, and the suspected causative agent if identified.

• Differentiate from Stevens-Johnson Syndrome (SJS) (L51.1) based on the percentage of body surface area involved; TEN typically involves >30% epidermal detachment.
• Code any associated adverse drug effects (T36-T50 with 5th or 6th character 5) as an external cause code, if applicable.
• Consider sequencing this code as the principal diagnosis when it is the primary reason for admission or treatment.