Stevens-Johnson syndrome vs Toxic epidermal necrolysis
How to tell Stevens-Johnson syndrome and Toxic epidermal necrolysis apart when a board question makes them look alike.
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Percent body surface area detached is the key discriminator, below 10 percent for SJS and above 30 percent for TEN.
Side by side
Widespread targetoid rash with mucosal involvement and epidermal detachment under 10 percent body surface area indicates Stevens-Johnson syndrome.
Mucocutaneous necrosis with epidermal detachment over 30 percent body surface area indicates toxic epidermal necrolysis.
Drug-triggered cytotoxic T-cell injury causes keratinocyte apoptosis and epidermal sloughing.
A more extensive form of the same immune-mediated epidermal necrosis causes severe barrier loss and systemic complications.
Clinical diagnosis uses Nikolsky-positive epidermal detachment with BSA involvement below 10 percent and mucosal erosions in at least one site.
TEN is diagnosed when epidermal detachment exceeds 30 percent BSA, often with electrolyte abnormalities, rising BUN, and high infection risk requiring burn-level monitoring.
The trap
Treating severe drug eruption as simple allergy and discharging with oral antihistamines delays life-saving supportive care. Any mucosal necrosis with epidermal detachment warrants immediate culprit drug cessation and high-acuity admission.
The repair move
Next best step: stop the offending drug immediately, transfer to burn or intensive care setting, begin aggressive fluid and electrolyte replacement, provide wound and ocular care, and monitor for sepsis. Use SCORTEN severity assessment to guide prognosis and escalation, with dermatology and critical care co-management.
Try a free question
CoreA patient has mucosal erosions, positive Nikolsky sign, and 35 percent epidermal detachment after starting allopurinol. What is the next best step in management?
Show answer and explanation
Answer: A. Immediate drug withdrawal and transfer to burn-level supportive care. This is TEN, and survival depends on immediate culprit drug cessation and intensive supportive care.
Why the other choices are tempting
- B. Wrong. Outpatient topical therapy is dangerously insufficient.
- C. Wrong. Fluid losses are substantial and require replacement.
- D. Wrong. Outpatient follow-up is unsafe in extensive epidermal detachment.
- E. Wrong. Continued exposure worsens epidermal necrolysis.
Flashcards
Tap a card to flip it.
What numerical cutoff separates Stevens-Johnson syndrome from TEN most reliably?
Extent of epidermal detachment by body surface area, under 10 percent for SJS and over 30 percent for TEN.
What early management step is mandatory for both SJS and TEN?
Immediate discontinuation of the culprit medication.
Quick answers
What is the fastest way to tell Stevens-Johnson syndrome from Toxic epidermal necrolysis?
Percent body surface area detached is the key discriminator, below 10 percent for SJS and above 30 percent for TEN.
What is the key clue for Stevens-Johnson syndrome?
Widespread targetoid rash with mucosal involvement and epidermal detachment under 10 percent body surface area indicates Stevens-Johnson syndrome.
What is the key clue for Toxic epidermal necrolysis?
Mucocutaneous necrosis with epidermal detachment over 30 percent body surface area indicates toxic epidermal necrolysis.
What is the common trap with Stevens-Johnson syndrome vs Toxic epidermal necrolysis?
Treating severe drug eruption as simple allergy and discharging with oral antihistamines delays life-saving supportive care. Any mucosal necrosis with epidermal detachment warrants immediate culprit drug cessation and high-acuity admission.