Differential Diagnosis

  • Livedo reticularis
  • Cholesterol emboli
  • Erythema ab igne
  • Systemic lupus erythematosus


This patient was diagnosed with erythema ab igne (literally, in Latin, redness from fire), a hyperpigmentation disorder caused by long-term exposure to heat. The most common sources include hot water bottles, electric blankets, and even laptop computers.


  • Although actual burns do not occur from the heat source in erythema ab igne, the skin develops a course pigmentation that appears as patches that are pink, purple, and eventually brown
  • Pruritus or mild burning paresthesias may occur
  • Resultant pigmentation changes can be permanent; there is no effective treatment


Pearls for Urgent Care Management and Considerations for Transfer

  • Caution the patient to avoid prolonged exposure to the heat source
  • Follow-up with a dermatologist is warranted to establish a new “baseline” against which future changes in pigmentation can be measured, in the interest of vigilance for cutaneous malignancies


Acknowledgment: Images courtesy of VisualDx.

A 45-Year-Old Woman with Suddenly Discolored Skin
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