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Nascer e Crescer

Print version ISSN 0872-0754On-line version ISSN 2183-9417

Nascer e Crescer vol.27 no.1 Porto Mar. 2018




Dermatology case


Caso dermatológico



Sílvia CamõesI, Manuela SeloresII,III

General and Family Medicine, Unidade de Saúde Familiar Espaço Saúde, Agrupamento de Centros de Saúde do Porto Ocidental. 4150-502 Porto, Portugal.
II Department of Dermatology; Research Unit in Dermatology, Centro Hospitalar do Porto. 4099-001 Porto, Portugal.
III Unit for Multidisciplinary Research in Biomedicine, Instituto de Ciências Biomédicas Abel Salazar. 4050-313 Porto, Portugal.

Correspondence to




We report the case of a child with a laptop-induced erythema ab Igne.

Erythema ab Igne is an hyperpigmented and reticulated erythema that results from prolonged thermal radiation exposure insufficient to cause burn.  It has been described in patients using portable electronics devices including laptops. The lesions are characteristically located on the thighs and asymmetric (left side). The diagnosis is based on the clinical appearance of the lesions and exposure history. The treatment is the avoidance of heat source.

Keywords: Dermatosis, erythema, laptop computer.


Relatamos o caso de uma criança com um eritema ab Igne induzido pelo computador portátil.

Eritema ab Igne consiste num eritema reticulado e hiperpigmentado que resulta da exposição prolongada à radiação térmica insuficiente para causar queimadura. Foi descrito em pacientes que utilizam dispositivos eletrónicos portáteis, incluindo computadores portáteis. As lesões estão caracteristicamente localizadas nas coxas e são assimétricas (lado esquerdo). O diagnóstico baseia-se na aparência clínica das lesões e na história de exposição. O tratamento é evitar a fonte de calor.

Palavras-chave: Computador portátil, dermatose, eritema.



A eleven-year-old boy, with no relevant pathological history or usual medication, was referred to Dermatology consultation due to asymptomatic cutaneous lesion in the anterior region of the left thigh with one year of evolution.

Physical examination revealed a macular lesion, with imprecise limits, reticulated pattern of erythematous-violet coloration, located on the anterior region of the left thigh (Figures 1 and 2). The lesion was painless to the touch and did not disappear with digital pressure. Remaining physical examination with no other relevant findings.





What is your diagnosis?



Laptop Computer-Induced Erythema ab Igne.



Erythema ab Igne consists of a localized reticular erythematous and posteriorly pigmented, sometimes, telangiectatic dermatosis, caused by prolonged and repeated exposure to heat.1 The lesions are located in the areas of incidence of the heat source, having irregular contours due to the interposition between the skin and the clothing.

Temperatures between 43 and 47oC are sufficient to cause these lesions.2

Numerous sources of heat were reported as the cause of these lesions. In the elderly, erythema ab Igne develops due to the abusive use of hot compresses or electric blankets.3 Repeated or prolonged exposure to a heater, steam radiator or brazier is a common cause.

The lesions are very characteristic; initially a slight transient erythema develops, but with prolonged and repeated exposure the lesion becomes permanent, with a reticular and hyperpigmented appearance.1,2 Exceptionally it can develop malignancy for squamous cell carcinoma.1,2

Some differential diagnoses with dermatosis that manifest with poikiloderma, livedo reticularis, vasculitis and contact dermatitis should be considered. The diagnosis is clinical and the treatment is the eviction of the heat source. Complete resolution of the lesions may occur in months if they are still in an early stage. In case of doubt biopsy of the lesion may be performed.2

Laptop Computer-Induced Erythema ab Igne is a dermatosis in rise and has appeared in younger and younger ages. Characteristically it is located on the thighs and is asymmetrical, more typically on the left thigh. The heat source comes from the battery or the fan normally located on the left side.3,4

In this case the child referred prolonged use of the laptop on the thighs (two to three hours a day).

Based on the history and clinical findings a diagnosis of erythema ab igne secondary to laptop use was made. The use of a protective pad was recommended and an appointment was scheduled in three months. At the second visit, there was minimal clinical improvement, and counselling was reinforced.

The recent popularity of laptop computers and other electronics emitting strong heat has made erythema ab igne a problem in younger generations.



  1. Bolognia JL, Jorizzo JL, Schaffer JV. Dermatology. Third edition. Elsevier; 2012.

  2. AL-Otaibi L. Erithema Ab Igne. Outubro, 2016. (Accessed 11 January 2017). Available at:

  3. Arnold A, W Itin P. Laptop Computer-Induced Erythema ab Igne in a Child and Review of the Liturature. Pediatrics. 2010; 126:e1227-30.

  4. Riahi R, Cohen P. Laptop-induced erythema ab igne: report and review of literature. Dermatology Online Journal. 2012; 18:5.




Sílvia Camões
General and Family Medicine
Unidade de Saúde Familiar Espaço Saúde
Agrupamento de Centros de Saúde do Porto Ocidental
Rua do Molhe 181,
4150-502 Porto

Received for publication: 07.02.2017 Accepted in revised form: 20.02.2017

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