Erythema Ab Igne Associated With Prolonged Direct Skin Contact With a Space Heater: A Case Report

Erythema ab igne is a rare condition manifesting in a reticulated, hyperpigmented rash that develops from chronic exposure to direct heat or infrared radiation. Diagnosis is clinical, with biopsy only required when malignancy is suspected. Historically, individuals repeatedly exposed to direct heat, such as bakers and metalworkers, were at increased risk, but since the development of central heating, incidence has significantly decreased in developed countries. However, it is important to recognize that erythema ab igne may occur with prolonged chronic exposure to normally functioning heated items such as car seats and, in our case, a space heater. The mainstay of treatment is the removal of heat exposure; delays in diagnosis and ongoing heat exposure can result in permanent pigmentation or progression to malignant transformation, leading to Merkel cell carcinoma, basal cell carcinoma, and squamous cell carcinoma. We describe a case of a woman who presented with complaints of cramping pain in her legs with discoloration and a lacy rash, particularly around her calves and moving upward toward her inner legs, who we determined had erythema ab igne caused by multi-hour direct exposure of her skin to a space heater placed in between her legs on a daily basis for the past few months. The treatment recommended was to avoid ongoing heat exposure; the patient was counseled extensively on the importance of stopping the use of space heaters for prolonged periods of time near her legs and discharged in stable condition.