Question

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)

Answer

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)

References

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