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Our Dermatol Online.  2014; 5(4): 430-431
DOI:.  10.7241/ourd.20144.26
Date of submission:  21.07.2014 / acceptance: 03.09.2014
Conflicts of interest: None


Cesar Bimbi1, Piotr Brzezinski2

1Member of Dermatological Comittee of State Medical Council of Rio Grande do Sul Brazil, Brazilian Society of Dermatology
2Department of Dermatology, 6th Military Support Unit, Ustka, Poland

Corresponding author:  Dr. Cesar Bimbi    e-mail:

How to cite this article: Bimbi C, Brzezinski P. Laptop-induced Erythema ab Igne – a case report. Our Dermatol Online. 2014; 5(4): 430-431.


Erythema ab igne is now more commonly related to heating pads, water bottles, infrared lamps and laptop computer use with skin contact. Heat damages superficial skin vessels leading to vasodilatation and leakage of blood and deposition of hemosiderin that presents in a net form. Any surface of the body is susceptible but mostly lower limbs, lower back and abdomen areas are affected.
Case Report
A 8-year-old boy presented with a four month history of dark brown pigmentation only to the anterior aspects of right and left thighs, symetrically (Fig 1). The distribution was reticular, the lesions were not blanchable and there were no symptoms. There was no need of biopsy since clinical diagnosis of erythema ab igne was obvious. His mother mentioned the fact of him using laptop positioned atop thighs (Fig. 2). Using his anterior thighs to prop up his laptop – and she added the fact that he used to work on his computer in that position several hours and every day.
Figure 1. Dirty appearing eruption of reticulate violaceous brown patch on anterior thighs.
Figure 2. Laptop positioned atop thighs in a 8-year-old boy.
Erythema ab igne is rare and not commonly seen on daily practice. It was once related to standing long periods of time in front of open fires or stoves to warm the body or using water bottles or heating pads for chronic backache. With introduction of heating systems it turned out to be a rare condition at least in developed countries. Bakers and foundrymen are at occupational risk. Heat damages superficial skin vessels leading to vasodilatation and leakage of blood with deposition of hemosiderin that presents in a net form [1]. It is very characteristic and one of those clinical features that deserves dermatologycal saying that “once seeing, never forgotten“. Nevertheless, Livedo Reticularis [2] can be a point of confusion but then the changes are to be strictly symetrical and telangiectatic. Laptop use is a modern inducer of this reaction [3,4]. Concentrated infrared radiation at the bottom of the laptop heats the skin only not enough to burn it but sufficient to affect skin superficial vessels. With the passage of time, the repeated heating leads to Erythema ab igne [5,6]. Always good to keep in mind that heat damage has been also associated with skin cancer and Merkel carcinoma. There may be epithelial cellular atypia resembling actinic damage, and some cases eventually go to thermal keratosis and squamous cell carcinomas [7,8]. Educate patients on avoiding prolonged laptop to thigh contact is essential. With removal of the heat source from the skin, no further treatment is required. The skin changes usually clear spontaneously in several weeks to months, if the repeated exposure to heat is discontinued.
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