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 (skin involvement only) or Erythema multiforme major (involves skin and one or more mucous membranes)


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