Toxic Epidermal Necrolysis

Toxic Epidermal Necrolysis is a topic covered in the 5-Minute Emergency Consult.

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Basics

Description

  • One of the most fulminant and potentially fatal of all mucocutaneous disorders
  • Skin sloughing at the dermal–epidermal interface results in the equivalent of a second-degree burn
  • Can affect up to 100% of total body surface area (BSA)
  • May extend to involve:
    • GI mucosa
    • Respiratory mucosa
    • Genitourinary/renal epithelium
  • Mechanism believed to be linked to T-cell–mediated cytotoxicity
    • A delayed type hypersensitivity reaction triggered by specific drugs, infections, or idiopathic triggers
    • Genetic susceptibility also appears to play a role
  • Toxic epidermal necrolysis (TEN) is included in a disease continuum with Stevens–Johnson syndrome (SJS). Current classification system includes 3 categories based on percentage of total BSA:
    • SJS: <10% of BSA
    • SJS–TEN overlap syndrome: 10–30% of BSA
    • TEN: >30% of BSA, can affect up to 100% BSA
  • Risk factors:
    • Age 1–10
    • Age >70
    • HIV
    • Active malignancy particularly hematologic
    • Liver and kidney disease
    • Genetic factors have been identified such as certain HLA types
  • Mortality rate overall ranges from 10% for SJS to up to 34% for TEN, usually due to secondary sepsis, acute respiratory distress syndrome (ARDS), and multisystem organ failure
  • Synonym(s):
    • Lyell syndrome
    • Epidermolysis necroticans combustiformis

Pediatric Considerations
  • A recent study found lower mortality rates in children: 0% SJS, 4% SJS/TEN, and 16% TEN
  • Predictors of mortality in children include: Renal failure, sepsis, epilepsy, any bacterial infection and malignancy

Etiology

  • Dose-independent drug reactions are the usual cause of TEN:
    • Onset time varies, most commonly 4–28 d from initiation of medication, but may be delayed up to 30 wk
    • Frequently implicated drugs include:
      • Sulfonamide and PCN antibiotics
      • Anticonvulsants (carbamazepine, phenytoin, phenobarbital, lamotrigine)
      • NSAIDs (oxicams, pyrazoles, sulindac)
      • Allopurinol
      • Corticosteroids
      • Antiretroviral drugs
      • Herbal remedies
      • New biologic agents
  • Other rare causes: Infections, specifically Mycoplasma pneumoniae in children, graft-versus-host disease, vaccinations, idiopathic cases (combined <4%)

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Basics

Description

  • One of the most fulminant and potentially fatal of all mucocutaneous disorders
  • Skin sloughing at the dermal–epidermal interface results in the equivalent of a second-degree burn
  • Can affect up to 100% of total body surface area (BSA)
  • May extend to involve:
    • GI mucosa
    • Respiratory mucosa
    • Genitourinary/renal epithelium
  • Mechanism believed to be linked to T-cell–mediated cytotoxicity
    • A delayed type hypersensitivity reaction triggered by specific drugs, infections, or idiopathic triggers
    • Genetic susceptibility also appears to play a role
  • Toxic epidermal necrolysis (TEN) is included in a disease continuum with Stevens–Johnson syndrome (SJS). Current classification system includes 3 categories based on percentage of total BSA:
    • SJS: <10% of BSA
    • SJS–TEN overlap syndrome: 10–30% of BSA
    • TEN: >30% of BSA, can affect up to 100% BSA
  • Risk factors:
    • Age 1–10
    • Age >70
    • HIV
    • Active malignancy particularly hematologic
    • Liver and kidney disease
    • Genetic factors have been identified such as certain HLA types
  • Mortality rate overall ranges from 10% for SJS to up to 34% for TEN, usually due to secondary sepsis, acute respiratory distress syndrome (ARDS), and multisystem organ failure
  • Synonym(s):
    • Lyell syndrome
    • Epidermolysis necroticans combustiformis

Pediatric Considerations
  • A recent study found lower mortality rates in children: 0% SJS, 4% SJS/TEN, and 16% TEN
  • Predictors of mortality in children include: Renal failure, sepsis, epilepsy, any bacterial infection and malignancy

Etiology

  • Dose-independent drug reactions are the usual cause of TEN:
    • Onset time varies, most commonly 4–28 d from initiation of medication, but may be delayed up to 30 wk
    • Frequently implicated drugs include:
      • Sulfonamide and PCN antibiotics
      • Anticonvulsants (carbamazepine, phenytoin, phenobarbital, lamotrigine)
      • NSAIDs (oxicams, pyrazoles, sulindac)
      • Allopurinol
      • Corticosteroids
      • Antiretroviral drugs
      • Herbal remedies
      • New biologic agents
  • Other rare causes: Infections, specifically Mycoplasma pneumoniae in children, graft-versus-host disease, vaccinations, idiopathic cases (combined <4%)

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