Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN)
Overview
Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are a spectrum of rare, life‑threatening mucocutaneous reactions characterised by widespread epidermal necrosis and detachment with painful skin lesions and mucosal erosions.
They are typically immune‑mediated (T‑cell cytotoxicity) and most commonly triggered by drugs; infections (notably Mycoplasma pneumoniae) and, rarely, vaccinations or malignancy can also precipitate disease.
Early recognition, prompt withdrawal of the suspected trigger, supportive resuscitation and urgent specialist referral (dermatology, burns/ICU, ophthalmology) are essential (NICE CG183; MHRA; RCEM).
Classification by BSA
> 30% |
(TBSA = total body surface area)
Aetiology and pathogenesis
- Mechanism: predominantly T‑cell-mediated keratinocyte apoptosis leading to full‑thickness epidermal necrosis.
- Common triggers: drugs (most frequent - e.g., anticonvulsants, sulfonamide antibiotics, allopurinol, nevirapine; latency typically 1-3 weeks after a new drug), infections (Mycoplasma), and rare post‑vaccination cases.
- Clinical principle: stop any suspected causative drug(s) immediately and document details (name, formulation, timing) - follow MHRA/NICE advice to withdraw suspected agents pending specialist review.