Erythema multiforme

Background

• Now considered a separate entity from Stevens-Johnson syndrome
• More common in young adults, but can develop at any age
• Classified as either:
  • Minor: localized eruption with mild or no mucosal involvement
  • Major: skin and mucosal erosions of raised atypical target lesions

Etiologies

• Drugs
  • Antimicrobials
    • Penicillins
    • Sulfonamides
    • Tetracyclines
    • Azithromycin
    • Antiretrovirals, particularly nevirapine
    • Fluconazole
  • Antiepileptics
    • Phenytoin
    • Carbamazepine
    • Valproic acid
    • Lamotrigine
  • Others
    • NSAIDs
    • Ethosuximide
    • Cocaine
    • Salicylates
    • Barbiturates
    • Allopurinol
• Infections
  • Herpes simplex virus, types 1 and 2 (most common)
  • Mycoplasma pneumoniae
  • Other viruses: parapoxvirus, varicella zoster virus, adenovirus, EBV, CMV, viral hepatitis, coxsackievirus, parvovirus B19, HIV
  • Chlamydia psittaci
  • Salmonella
  • Histoplasmosis
  • Tuberculosis
  • Dermatophytes

Clinical Manifestations

• Asymptomatic, erythematous discrete macules and papules
• Lesions may have target-like, iris, or bullseye appearance
• Most common on hands, wrists, and ankles
• Mucosal involvement of oral cavity is common
  • Tongue, palate, buccal mucosa, and gingiva are all commonly involved