Erythema ab igne

Erythema ab igne is a rash of the skin, which is usually caused by the long-term exposure to heat or infrared radiation, and which is not a burn. Usually the name is abbreviated "EAI". Other names include hot water bottle rash fire stains, laptop thigh, granny's tartan and toasted skin syndrome.
Some people may complain of mild itchiness and a burning sensation. When a change in skin pigmentation can not be seen, it is often not noticed at all.