by Alicia M Prater PhD

Created on: October 08, 2010

Anyone who has used a laptop actually on their lap for a lengthy period of time knows that the battery compartment and underside of the fan area get hot, sometimes up to 125 degrees Fahrenheit. Some electronics stores even sell lap cooling trays to prevent the heat from reaching the user’s legs. However, the case of a 12-year-old with mottled skin after using a laptop for a few hours a day for a couple of months has some wanting a warning placed on the devices by laptop manufacturers, though many already warn to avoid direct contact with the skin when placing the computer on one’s lap (

YahooNews).

Toasted skin syndrome, or heat induced circumscribed dermal melanosis (also known as erythema ab igne), has been described in a number of cases in which an individual used a hot object directly and repeatedly on their skin – a hot water bottle for instance (specific case described in Western Journal of Medicine, 2000) - or from exposure to open fires and coal stoves (WebMD). The fire-like rash is caused by the absorption of the irradiated heat. This condition is also seen with laptop users – 10 such cases have been reported in medical journals in the last 6 years according to CBS News.

Laptop users who are affected by toasted skin syndrome exhibit a sponge or net-like pattern of brownish red lines on the affected area, generally on the upper leg or thigh, sometimes one or both depending on the user’s placement of the device. The condition as caused in this context is being dubbed “laptop-induced dermatosis” and was first described in 2004. The condition may clear up, or the altered pigmentation may be permanent. Some doctors fear that some people may even be at risk for skin cancers, though no cancer cases have been reported. Chronic, prolonged inflammation of the skin can increase the risk for squamous cell carcinoma, and under the microscope, skin affected by toasted skin syndrome appears sun damaged.

Though the condition is usually caused by heat that isn’t hot enough to cause burns (109 degrees F and more), the temperature needed to cause toasted skin syndrome is between 111 and 112 degrees Fahrenheit, with exposure occurring for 6 to 8 hours a day over several weeks or months. Children’s skin may be more sensitive and develop the syndrome more quickly. Preventing direct contact between the bottom of the laptop and one’s skin can prevent the heat from being absorbed, and prevent the dermatosis.

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