A 20-year-old man presented with a well defined, brown, mildly erythematous, reticulated patch lesion on his left thigh (Figure). Although livedo reticularis could be suggested, the clinical presentation was in keeping with erythema ab igne.
On questioning, the patient described the frequent use of a laptop on his thighs, with the heat source on the left side. Erythema ab igne can be precipitated by any heat source (eg, hot water bottles, heating pads). We recommended that he cease using the laptop directly on his lap or place the laptop on a hard surface.
Publication of your online response is subject to the Medical Journal of Australia's editorial discretion. You will be notified by email within five working days should your response be accepted.