Laptop heat exposure causes rare skin rash and discoloration

Balancing an electronic device on bare skin risks disfiguration, doctors warn in the online journal BMJ Case Reports, after treating a child with skin discoloration and a 'fishnet' rash -hallmarks of erythema ab igne-caused by repeated exposure to the low grade heat from a laptop.

Although historically more common in adults, as a result of hot water bottle and heated pad use, the condition is becoming increasingly common in children due to the prevalence of electronic devices, they highlight.

Their patient, a pre-teen boy, presented with an abdominal rash and what appeared to be spontaneous bruising, which he had had for a week. Neither he nor his parents were able to think of a likely trigger.

He was initially suspected of having a liver injury following minor trauma. But his blood test results and abdominal scans were normal, and he was discharged.

But a fortnight later, he turned up at hospital again. The rash had progressed, and had become more tender, with areas of skin peeling.

On further questioning, the boy revealed that he was being home-schooled and routinely used a laptop for educational activities. He explained that he rested his laptop on his abdomen for up to 8 hours a day, often while charging it.

He was diagnosed with erythema ab igne, and advised to stop resting his laptop on his body. A phone consultation with his father several months later indicated that the condition had gradually improved and that the rash had disappeared.

"The increasing use of electronic devices, particularly during home schooling, has emerged as an under-recognized cause of [erythema ab igne] in pediatric populations," point out the report authors. 

Usually, the condition clears up when the heat source is removed, but "rarely, chronic exposure may result in persistent pigmentation or, in longstanding cases, malignant transformation," they warn.