Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Classification and Management

Classification Based on Epidermal Detachment

The British Journal of Dermatology guidelines state that Stevens-Johnson Syndrome (SJS) has an epidermal detachment of less than 10% of the body surface area (BSA), while Toxic Epidermal Necrolysis (TEN) has an epidermal detachment of more than 30% BSA 1, 2, 3
SJS is characterized by an epidermal detachment of less than 10% BSA, accompanied by widespread purpura or atypical flat targets 1, 2, 3
Overlap SJS-TEN is characterized by an epidermal detachment of 10-30% BSA, accompanied by widespread purpura or atypical flat targets 1, 2, 3
TEN is characterized by an epidermal detachment of more than 30% BSA, with or without purpura or target lesions 1, 2, 3

The mortality rate for SJS is 0-3.1% in adults and 0% in children 2, 3
The mortality rate for TEN is 17-25% in adults and 8.5-14.7% in children 2, 3
The mortality rate for Overlap SJS-TEN is 14.3% in adults and 3.9-25% in children 2, 3

Both SJS and TEN have similar clinical characteristics, including skin lesions, a positive Nikolsky sign, and mucosal involvement 4, 6, 7
The skin lesions are characterized by dark red macules with a central dark red spot surrounded by a pink ring, which later confluence 4, 6
The Nikolsky sign is positive, with the epidermis peeling off with minimal lateral pressure on the skin lesion 4, 6, 7
Mucosal involvement, including the eyes, mouth, nose, and genitals, is common in both conditions 6

The classification of SJS and TEN determines the level of care required, with patients having an epidermal detachment of more than 10% BSA requiring immediate treatment in an intensive care unit or burn center 5
Patients with an epidermal detachment of more than 30% BSA and clinical deterioration may require surgical intervention in addition to conservative treatment 1, 8

Accurate documentation is crucial, with separate recording of the extent of erythema and epidermal detachment on a body map, as epidermal detachment (not erythema) determines classification and prognosis 5, 6
The epidermal detachment includes both already detached epidermis (visible erosion and blisters) and detachable epidermis (areas with a positive Nikolsky sign) 5
Immediate withdrawal of the suspected causative drug is the best way to improve prognosis 3