Erythema ab igne (EAI) was a very common disease in the past, when it occurred mainly among people who worked with fire, or in people who had used heat sources in contact with the skin for warming purposes for long time. In the last decades, with the introduction of central heating in the buildings, EAI incidence was remarkably decreased in Western Countries, and it was found almost exclusively among elderly, and in people affected by defects in thermoregulation or alteration of periphery circulation. Recently, a new slight increase of EAI prevalence has been observed, although with some new features. Here, we describe three cases of adolescents who presented with brownish, reticulated patch on the anterior surface of their thighs. An accurate medical questioning revealed that the patients used to place the lower surface of laptop computer on the extensor side of their thighs in a cross-legged position for many hours (about 6-8 hours) every days. In particular, the patients supported the laptop computer always on the same leg. Laptop computer-induced EAI was diagnosed. Only a few cases of laptop computer-induced EAI have been reported in the literature. Although EAI is poorly symptomatic and it generally evolve to complete remission after a early discontinuance of heat source exposure, chronic lesions of EAI have been regarded as precancerous lesions. Therefore, it is important to implement diagnosis and prevention measures of this disease. Dermatologists should consider new causal agents for old diseases
