UMEM Educational Pearls


Patient presents after being started on an antibiotic for cellutlitis of lower extremity. What's the diagnosis and what are some other etiologic agents (name 3)


Erythema Multiforme (minor)

  • Acute, self-limited rash affecting the skin; mucus membranes are spared in the minor variant although EM major involves one mucus membrane.
  • Erythematous, macupapular, and blanching with central clearing; it is often puritic
  • Several etiologic factors that have been identified. Most commonly:
    • Infections: viral (e.g., HSV), bacterial (e.g., strep), fungal (e.g., histoplasmosis)
    • Drugs: antibiotics (e.g., sulfa drugs, PCN, etc.), NSAIDs
    • Miscellaneous: collagen vascular diseases, pregnancy, and malignancy
  • It is self-limiting and will resolve in 2-6 weeks.
  • Treat by stopping offending agent and supportive care (e.g., diphenhydramine for purtitis)


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