The father of a 10-year-old boy was concerned about the asymptomatic rash on his son’s anterior thighs that had persisted for 9 months. The macular, reticular, erythematous rash hadevident hyperpigmentation bilaterally. The child had been otherwise healthy.
The father of a 10-year-old boy was concerned about the asymptomatic rash on his son’s anterior thighs that had persisted for 9 months. The macular, reticular, erythematous rash had
evident hyperpigmentation bilaterally. The child had been otherwise healthy. He was not taking
any medications and had no history of recent trauma or travel. There was no family history of a similar rash. Two other providers had assessed the rash and were unable to determine a cause.
Further questioning revealed that the child had received a laptop computer about a year earlier and had been using it for at least 2 hours almost every day, often with it propped up on his thighs.
Erythema ab igne occurs when skin is repeatedly exposed to infrared radiation. It has been reported with the use of laptop computers.1 Other reported causes include open fires, heating pads, hot water bottles, heated recliners, and car heaters. Heated popcorn kernels when applied to skin to reduce arthritis pain have also caused erythema ab igne.2
The repeated exposure to moderate heat from an external heat source can result in persistent reticular erythematous patches, telangiectasia, and chronic hyperpigmentation. Patients commonly report mild pruritus and burning. Rarely, affected areas may become bullous or hyperkeratotic. In patients with severe erythema ab igne, poikilodermatous changes may result.
Discontinuation of chronic heat exposure is the first line of treatment. The skin changes often gradually resolve over several months. In severe cases with persistent pigmentation, photothermolysis laser treatment may be beneficial.
Levinbook WS, Mallett J, Grant-Kels JM. Laptop computerâassociated erythema ab igne.
Donohue KG, Nahm WK, Badiavas E, et al. Hot pop brown spot: erythema ab igne induced by heated popcorn.