Erythema multiforme

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  • Erythema Multiforme (EM) is an acute, self-limited skin condition
  • Peak incidence in second and third decades of life
  • Despite multiple associations, thought to be triggered by HSV in most cases
  • Usually self-limited and resolves within 2-6 weeks; may recur
  • Wide spectrum of severity
    • Classified as Erythema multiforme minor or Erythema multiforme major


Clinical Features

Erythema Multiforme
Erythema multiforme minor of the hand (note of make of the blanching centers of the lesion)
  • Erythematous or violaceous macules, papules, vesicles, or bullae
  • Target lesions with “three zones of color” are the hallmark of EM
  • Distribution is usually symmetric, most commonly involving palms/soles, the backs of the hands/feet, and/or the extensor surfaces of the extremities
  • Not to be confused with SJS/TEN, which are now considered separate from the EM spectrum

Erythema multiforme minor

  • Typical targets or raised, edematous papules distributed peripherally
  • No mucous membrane involvement

Erythema multiforme major

  • Same as EM minor + involvement of 1+ mucous membranes
  • Epidermal detachment involves < 10% of total body surface area
  • Some cases can be severe or even fatal

Differential Diagnosis

Erythematous rash

Vesiculobullous rashes




  • Usually made clinically
  • In severe cases, work-up includes basic labs and cultures
  • Punch biopsy: to confirm the diagnosis and to rule out other diagnoses (looks different from SJS/TEN histologically)


  • Search for underlying cause
    • Prompt withdrawal of suspected drug/agent causing symptoms
  • Symptomatic treatment
  • Consultation (rarely) with the following may be necessary: dermatologist, ophthalmologist, burn surgeon


  • For mild cases, treat as above with dermatology follow-up
  • For severe cases with multiple lesions / severe mucous membrane or tracheobronchial involvement with impaired PO intake, dehydration, or secondary infection: inpatient admission
    • May require specialized ICU or burn unit care

See Also

External Links


  1. Lamoreux MR, Sternbach MR, Hsu WT (December 2006). Erythema multiforme. Am Fam Physician 74 (11): 1883–8. PMID 17168345