“He recognized that the laptop got hot on the left side,” the researchers write. “However, regardless of that, he did not change its position.”

Researchers from Switzerland, reporting in the Nov. 5 issue of Pediatrics , focus on the case of a 12-year-old boy who developed a sponge-patterned discoloration on his left thigh after playing computer games with his laptop resting on his upper legs a few hours per day for several months.

The “syndrome” consists of a brownish discoloration of the skin caused by prolonged exposure to heat from the computer.

Oct. 4, 2010 -- People who spend prolonged periods of time studying, reading, or playing games on laptop computers resting on their upper legs could develop “toasted skin syndrome,” a case report shows.

Other ‘Toasted Skin’ Cases Have Been Reported

The researchers say the boy is the youngest of 10 reported patients with the “laptop-induced dermatosis” since the condition was first described in 2004.

The condition can lead to permanent darkening of the skin, and in rare cases, damage that leads to skin cancers.

The heat that causes the condition originates from a laptop computer’s optical drive, the battery, or the ventilation fan.

The condition, technically called erythema ab igne, has been observed before on the lower legs of patients who worked in front of open fires or coal stoves. It also has been treated in elderly patients who used hot pads and blankets, according to the researchers.

The researchers say mild-to-moderate heat between 109.4 to116.6 degrees Fahrenheit is enough to cause burns. However, 111.2 degrees Fahrenheit is enough to cause toasted skin syndrome.

“Computer-induced lesions are typically found on only one leg because the optical drives of laptops are located on the left side,” the authors write. “The computer placed on a lap may completely or partially occlude [obstruct] the ventilation-fan exhaust.”

The researchers say that the 10 reported patients had lesions on one or both of their upper legs that developed after several weeks to months of laptop use of six to eight hours per day.

The authors say the condition can be prevented by using heat protection such as the laptop’s carrying case between the body and the computer.