Erythema ab igne: new technology rebounding upon its
, Marc Z. Handler,
, and Robert A. Schwartz,
MD, MPH, DSc (Hon)
Dermatology and Pathology, Rutgers New
Jersey Medical School, Rutgers University
School of Public Affairs and Administration,
Newark, NJ, USA
Robert A. Schwartz,
Dermatology, Rutgers New Jersey Medical
185 South Orange Avenue, MSB H-576
Conﬂicts of Interest: None.
Funding sources: None.
Erythema ab igne (EAI) is a persistent, chronic skin condition resulting from prolonged
exposure to infrared radiation, experienced as heat. Once associated with traditional
warming sources like wood burning stoves or open ﬁres, modern, infrared exposure
originates also from newer sources like laptops and heating pads and may be creating a
rebound of EAI. The epidemiology may be different too, with younger patients than
previously seen. Localized EAI over an area of pain in the abdomen or lower back can be
a sign of an underlying disorder, including cancer. Prognosis of EAI is good, with removal
of the heat source resulting in complete remission. In chronic cases in which premalignant
cutaneous dysplasia has resulted, additional treatments may be necessary including topical
retinoids, 5-ﬂuorouracil cream, and laser treatments. Rarely, cancers such as squamous
cell carcinoma, Merkel cell carcinoma, and cutaneous marginal zone B cell lymphoma have
been associated with longstanding EAI.
Modern society offers novel technological comforts to avoid
experiencing the cold, like heated car seats, heated blankets,
and portable space heaters. It also provides battery-powered
portable computers that facilitate work, playing videos games,
or updating social media from any space, even while resting in
bed; hence the name laptop. Still more, electric or battery-oper-
ated heating pads are replacing the hot-water bottle for local
pain relief. These modern conveniences have something in
common – they emit low levels of infrared radiation, experi-
enced as heat, and as such, pose increasing risk for the
develop of erythema ab igne (EAI). EAI was traditionally associ-
ated with exposure to open ﬁres and wood burning stoves,
which have been in decline with the technological advent of
Ironically, new technology is creating a
rebound of EAI, while low-technology infrared heat sources like
radiators and water bottles still persist. Still unusual, EAI may
be diagnostically challenging due to its infrequency.
Erythema ab igne (EAI) translates from the Latin as “redness
from ﬁre” and has also been called “toasted skin syndrome,”
and “granny’s tartan.”
It is a persistent, chronic skin condition
resulting from extended exposure to low grade heat (between
43 and 47 °C), which is just below the burning point.
can lead to a transient, blanchable, reticulated erythema. With
chronic exposure, EAI appears as a brownish reticulated, ery-
thematous, hyperpigmented and hypopigmented eruption, and
can be also characterized by cutaneous atrophy, telangiectasia,
and subepidermal bullae
(Fig. 1). Frequency, exposure time,
and heat source temperature inﬂuence the development of EAI,
which may develop from 2 weeks to a few months.
EAI is typi-
cally asymptomatic, although some people complain of a mild
burning sensation and pruritus.
Its histopathology may appear
relatively normal with only mild acanthosis and hyperpigmenta-
tion of basal keratinocytes.
The pathophysiology is still not fully elucidated. Repetitive long-
term exposure to infrared radiation (IR) likely promotes changes
in dermal elastic ﬁbers and involves the dermal venous plexus
from which the pattern of eruption follows.
also include epidermal atrophy, vasodilation, and dermal deposi-
tion of melanin and hemosiderin.
IR may cause changes in the
epidermis in a similar fashion as ultraviolet light.
has been shown to lead to an increase in skin temperature, pre-
cipitating thermoregulatory and local vasodilator responses when
tissue temperature rises toward 40 °C, increasing blood ﬂow in
the affected area, facilitating skin cooling.
ª 2017 The International Society of Dermatology International Journal of Dermatology 2018, 57, 393–396