SECTION EDITOR: MARY S. STONE, MD; ASSISTANT SECTION EDITORS: SOON BAHRAMI, MD; CARRIE ANN R. CUSACK, MD; SENAIT W. DYSON, MD; MOLLY A. HINSHAW, MD; ARNI K. KRISTJANSSON, MD
Histologic evaluation of a shave biopsy specimen revealed a mildly atrophic and effaced epidermis. Along the dermoepidermal junction, subtle vacuolar degeneration was seen. In the superficial dermis there was a mild, superficial mononuclear infiltrate associated with scattered extravasated erythrocytes. The findings in the biopsy specimen were nonspecific but consistent with the clinical suspicion of EAI.
Erythema ab igne was first described over 150 years ago as a reticulated pigmentation that occurred after prolonged exposure to infrared radiation. The amount of heat is insufficient to cause a burn and typically ranges from 43 °C to 47 °C. Historically, it was most often seen on the lower extremities of persons who worked or warmed themselves in front of an open fire, coal stoves, or radiators.1 Although there are multiple case reports of EAI caused from unusual heated sources, such as therapeutic recliners,2 transcutaneous electrical nerve stimulation device,3 a car heater,4 and even hot popcorn kernels,5 today, in developed countries where central heating is more common, it is most frequently caused by hot water bottles, heating pads, or electric blankets.2,4 Most recently, there have been several reports of unilateral leg EAI and 1 case of EAI of the left breast caused by prolonged use of laptops secondary to heat generated from the optical drives on the back of the computer.1,6,7
Erythematous Patches on the Chest —Diagnosis. Arch Dermatol. 2012;148(1):113-118. doi:10.1001/archderm.148.1.114-b