Laptops can cause ‘toasted skin syndrome’. (the picture on the right is an example of "’toasted skin syndrome’.)
In one recent case, a 12-year-old boy developed a sponge-patterned skin discolouration on his left thigh after playing computer games a few hours every day for several months.
"He recognised that the laptop got hot on the left side; however, regardless of that, he did not change its position," Swiss researchers reported in an article published in the journal Paediatrics.
I’ll do a full write-up when I get a copy of the Paediatrics.article.