Drug-Induced Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis Diagnosis and Management

Clinical Presentation and Diagnosis

SJS/TEN presents with flat atypical targets or purpuric macules with epidermal detachment, systemic symptoms, and involvement of multiple mucosal surfaces 1
EM typically presents with typical target lesions (dark red center, pink ring, well-defined circular appearance) predominantly on limbs and extremities, and is mostly related to HSV infection or Mycoplasma pneumoniae, not typically drug-induced 1, 2
The presence of neutropenia and significantly elevated liver enzymes makes EM less likely, as EM is usually a more benign hypersensitivity reaction without severe systemic involvement 1, 2
Nonspecific drug eruptions can present as maculopapular rashes, urticaria, or erythematous macules, but the presence of targetoid lesions with systemic involvement suggests a more severe reaction than simple drug eruption 3, 4, 5
Secondary bacterial infection would more likely present with purulence and localized inflammation rather than targetoid lesions 6

Determine if lesions show epidermal detachment or positive Nikolsky sign (pathognomonic for SJS/TEN) 1
Assess percentage of body surface area involved: <10% suggests SJS, 10-30% is SJS-TEN overlap, >30% is TEN 2
Examine for mucosal involvement (oral, ocular, genital) which is characteristic of SJS/TEN 2
Immediate skin biopsy showing full-thickness epidermal necrolysis with extensive keratinocyte apoptosis confirms SJS/TEN 5

Calculate SCORTEN to assess mortality risk and determine need for ICU transfer, considering factors such as age >40 years 4, heart rate >120 5, cancer/malignancy 6, body surface area involved >10% 2, serum urea >10 mmol/L 5, serum glucose >14 mmol/L 5, and serum bicarbonate <20 mmol/L 5
Obtain urgent dermatology consultation and consider transfer to burn unit or intensive care setting 5
Perform skin biopsy immediately to confirm diagnosis and exclude other blistering diseases 5
Consider high-dose intravenous immunoglobulin (IVIG) therapy if SJS/TEN confirmed, though evidence is mixed 5
Do not use systemic corticosteroids without specialist consultation, as their role in SJS/TEN is controversial and may increase infection risk 2
Provide meticulous supportive care including fluid/electrolyte management, wound care, and infection prevention, as these patients require burn unit-level care 7