Placing a laptop directly on your legs for extended periods can harm the skin. Dermatologists at University Hospital Basel in Switzerland recently reviewed ten cases of laptop-induced “toasted skin syndrome.” After regularly keeping computers on their laps for several hours a day, the patients developed a brown, mottled rash on one or both thighs, where the computer’s heat had injured the skin tissue, researchers say. It’s better to put something between your lap and device, such as a pillow, laptop case, or laptop desk, advices a clinical professor or dermatology at Boston University.