DermatologyTier 2Disease (DEADMAN)

Cutaneous manifestations of adverse effects of therapeutic interventions - toxic epidermal necrolysis

Description

Toxic epidermal necrolysis (TEN) - the most severe form of the Stevens-Johnson syndrome/TEN spectrum, a life-threatening drug reaction causing widespread epidermal detachment (>30% body surface area, distinguishing it from SJS <10% and SJS-TEN overlap 10-30%) from massive keratinocyte apoptosis

Rare but carries very high mortality (historically quoted around 25-30% for TEN, lower for SJS); classic culprit drugs include allopurinol, anticonvulsants (carbamazepine, lamotrigine, phenytoin), sulfonamides, and NSAIDs

A T cell-mediated cytotoxic reaction against keratinocytes, with HLA-B allele associations that vary by drug and ethnicity (e.g. HLA-B*15:02 for carbamazepine-induced SJS/TEN, particularly relevant in some Asian populations) - massive keratinocyte apoptosis causes full-thickness epidermal necrosis and detachment, analogous in severity/mechanism to an extensive burn

Widespread, painful, erythematous/dusky skin progressing to epidermal detachment/sloughing, positive Nikolsky sign, and mucosal involvement (oral, ocular, genital - often severe and a major source of long-term morbidity, particularly ocular scarring)
Onset typically 1-3 weeks after starting the causative drug; SCORTEN scoring at presentation helps predict mortality risk and guide the intensity of supportive care

Immediate cessation of the causative drug is the single most important intervention
Management in a burns unit or ICU-level setting is standard given the extensive epidermal loss - fluid/electrolyte management, temperature regulation, infection prevention/monitoring, and specialist wound care, analogous to major burn management
Ophthalmology involvement early is essential given the risk of severe, sight-threatening ocular scarring
Specific immunomodulatory treatments (IVIG, ciclosporin) are used in some centres, though evidence quality varies and management is generally centred on aggressive supportive care

HLA-B15:02 (carbamazepine), HLA-B58:01 (allopurinol), Stevens-Johnson syndrome (the less severe end of the same spectrum), ocular complications/blindness risk, mucosal scarring

TEN should be managed with the same urgency and supportive care intensity as a major burn, given the equivalent physiological consequence of extensive epidermal loss - early transfer to an appropriate specialist unit (burns/ICU) improves outcomes

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