DR


[Dermatology Reports 2010; 2:e11] [page 27]

Side-effects to the use 
of laptop computers: 
erythema ab igne
Lisa Linnea Søholm Secher, 
Dina Vind-Kezunovic, 
Claus Otto Carl Zachariae
Department of Dermatology, Copenhagen
University Hospital Gentofte, Denmark

Abstract 

The use of laptop computers is increasing,
and many children and young adults spend
hours with their laptops on their laps daily. We
report a case with erythema ab igne on the
thigh of a 17-year-old girl, induced by use of
laptop computers four to five hours daily for
nine months. 

Case Report

The use of laptop computers has become
popular over the last ten years. Computer tech-
nology is refined continuously and the need for
immediate access to information from the
Internet increases.
A 17-year-old girl with no past medical his -

tory presented with symptoms of burning and
itching experienced on the front of the left
thigh for nine months. On physical examin -
ation, there was a brown, reticular, non-
blanchable cutis marmorata on the left anteri-
or thigh, approximately the size of a palm
(Figure 1). Blood tests including ANA screen-
ing were normal. A skin biopsy showed mini-
mal dermal inflammation. The patient had not
been exposed to heat sources, such as radia-
tors, stoves, or hot-water bottles. On further
questioning, it was found that three months
before the symptoms appeared our patient pur-
chased a laptop, which she used four to five
hours daily. When asked directly, our patient
remembered that the discomfort of the area
often appeared when using the laptop. The lap-
top’s battery was localized at the left side of the
computer, which corresponded with the local-
ization of the rash. The diagnosis was erythe-
ma ab igne causae laptop.
The temperature on the thighs was meas-

ured after our patient had been sitting with the
laptop on her thighs for an hour (Figure 2).
The temperature started at 27°C on both

thighs, and after an hour the temperature of
the left and right thighs was 38°C and 33°C,
respectively.

Discussion

Erythema ab igne (“redness from fire”) is
seen rarely in young patients. The condition is
seen usually in elderly people exposed to heat-
ing from repeated applications of heating pads
or hot-water bottles. Erythema ab igne also
occurs in cooks and bakers exposed to stoves,1

and historically it was seen in workers shovel-
ing hot coals. The continuous exposure to
infrared radiation initially causes transient
erythema, progressing to reticulate pigmenta-
tion and keratosis. These lesions can develop
later into squamous cell carcinomas.2

Because erythema ab igne is a precancerosis
in line with actinic keratoses,3 it is important
to recognize this new cause of erythema ab
igne, especially as we must expect to see it
more in children in the coming years. If the
heat exposure is stopped early, the prognosis is

extremely good. Erythema ab igne may not be
the only side-effect to the use of laptops on the
thighs. Some studies suggest that the use can
influence male fertility. When laptops are
placed on the anterior aspects of the thighs,
the scrotal temperature rises approximately
three degrees after an hour, which perturbs
spermatogenesis, and hence can influence
male fertility.4

Although the name laptop invites using the
computers directly on the lap, we believe it is
necessary to warn about the possible side-
effects, as it may cause chronic damage to the
skin. Use of a protective blanket or plate is
advisable.

References

1. Bachmeyer C, Benaid P, Bégon E. Laptop
computer as a modern cause of erythema
ab igne. J Eur Acad Dermatol Venereol
2009;23:736-7.

2. Jagtman BA. Erythema ab igne due to lap-
top computer. Contact Dermatitits 2004;
50:105.

3. Bilic M, Adams BB. Erythema ab igne
induced by a laptop computer. J Am Acad
Dermatol 2004;50:973-4.

4. Sheynkin Y, Jung M, Yoo P, et al. Increase
in scrotal temperature in laptop computer
users. Hum Reprod 2005;20:452-5.

Dermatology Reports 2010; volume 2:e11

Correspondence: Lisa L.S. Secher, Callisensvej
12, 2.tv, DK-2900 Hellerup, Denmark.
E-mail: lisa.secher@webspeed.dk

Key words: laptop, erythema, side-effect, reticu-
late pigmentation.

Contributions: LLSS main idea, primary manu-
script written in Danish; DV-K translation to
English, proofreading; COCZ writing the main
manuscript, proofreading. 

Conflict of interest: the authors report no con-
flicts of interest.

Received for publication: 8 July 2010.
Accepted for publication: 8 July 2010.

This work is licensed under a Creative Commons
Attribution 3.0 License (by-nc 3.0).

©Copyright L.L.S. Secher et al., 2010
Licensee PAGEPress, Italy
Dermatology Reports 2010; 2:e11
doi:10.4081/dr.2010.e11

Figure 1. Erythema ab igne on the left thigh.

Figure 2. Our patient in her usual working
position with the laptop, while thigh tem-
perature was being measured.

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