We told you there were physical risks in putting your notebook on your lap and a case study from Switzerland just came out in the Novemeber 5 issue of Pediatrics to prove it. Researches documented several cases of "Toasted Skin Syndrome," a brownish discoloration of the skin caused by prolonged exposure to heat from laptop computers resting on their upper legs.
The focus of the study fell on a 12-year-old boy who developed a sponge-patterned discoloration on his left thigh—the same left side where many notebook processors, graphics chips, and heat exhausts lie —after playing computer games with his laptop resting on his upper legs for a few hours a day for several months.
The heat needed to burn skin can range from 109.4 to 116.6 skin which are reasonably approachable for laptop going at full load that has less than optimal ventilation sitting on a person's legs. Those temperatures aren't atypical as we've seen notebook bottoms get as hot as 125 degrees after only 15 minutes of use.
According to researchers this "laptop induced dermatosis" was first described in 2004. In the current study, 10 reported patients had lesions on one or both of their upper legs that developed after several weeks of laptop use for six to eight hours per day. The results of the syndrome can be worse than permanently discolored skin as in rare cases it can also lead to skin cancer.