Epidemiology

Etiology

• Drugs (most common trigger, ∼ 80% of cases)
  • Antibiotics: sulfonamides (e.g., TMP/SMX), aminopenicillins, rifampicin
  • Antiepileptics: phenytoin, phenobarbital, lamotrigine, valproic acid, carbamazepine, ethosuximide
  • Oxicam NSAIDs (e.g., piroxicam)
  • Allopurinol
  • Sulfasalazine
• Risk factors
  • HIV infection

Pathophysiology

The pathogenesis is not completely understood but is thought to involve a delayed hypersensitivity reaction (type IV): ↑ activity of drug-specific cytotoxic T cells → release of granulysin (a cytolytic protein) by an unknown mechanism → damage to keratinocytes

Clinical features

• Prodromal phase (begins 1–3 weeks after the intake of medication): high fever (usually > 39°C or 102°F), malaise, sore throat, myalgia and/or arthralgia
• Mucocutaneous lesions appear 1–3 days after the onset of prodromal symptoms
  • Cutaneous manifestation sequence
    1. Painful, erythematous/purpuric macules
       • May have a targetoid appearance (cockade lesions)
       • Typically seen over the face and trunk
    2. Lesions form bullae and/or vesicles; positive Nikolsky sign
    3. Extensive, full-thickness epidermal necrosis and sloughing (resembling large superficial burns)
  • Mucosal membranes: almost always involved
• Shock may develop

Diagnostics

Treatment