Erythema Ab Igne

What is Erythema Ab Igne

Erythema Ab Igne is a skin condition that is caused by long term exposure to heat.  It is often referred to as hot water bottle rash, laptop thigh, granny’s tartan, toasted skin syndrome or fire stains. It is an uncommon skin disorder that has a fish net like pattern of hyper pigmentation on the skin. The name means redness from  fire.  Woman have a higher chance then men to contract erythema ab igne.  It was once seen commonly in elderly people who sat too close to open fires or heat sources, but is also seen in young individuals.

Caueses of Erythema Ab Igne

Causes of erythema ab igne include repeated exposure to heated car seats, space heaters, and fireplaces, repeated application of hot water bottles or heated blankets (often used to treat pain), or resting a laptop on the thighs.  Occupations that can cause erythema ab igne include bakers, chefs, blacksmiths and jewelers. The form of heat range to cause damage to the skin is from 43 degrees C to 47 degrees C.

Symptoms associated to Erythema Ab Igne

Lesions on the skin are usually asymptomatic, but can be associated with itching, burning and pain. Often times the condition will go unnoticed until it is seen with the eyes.  The lesions start on the skin as small pink patches but will progress into reddish or brown reticulated patterns.  Multiple stages of the lesions can be present on the skin.  The fish net or lacy patterns on the skin are caused from injuries to the super vascular networks and the outer layers of skin after exposure to heat. The skin will often become thinner as does the underlying tissue, causing the lesions to form.  They are often described as blotchy looking.

Treatments for Erythema Ab Igne

Treatments for erythema ab igne include stopping the contact from the heat source. Often times the condition will resolve itself if there is  a mild case of it. If the skin is severely damaged, there is often not a chance to resolve it. In this case, squamous cell carcinoma or neuroendocrine carcinoma could form. Sores that do not heal, or grow to form a lump with a rash may need a skin biopsy performed to rule out skin cancer. Topical tretinoin can help to improve the appearance of the skin, as can laser treatments. If pre-cancerous changes are being made to the skin, a 5 fluorouracil cream can be prescribed.

The prognosis for treating erythema ab igne (EAI) is very good if the heat source is removed right away. If the heat source is not removed quick enough, there is a chance that pigmentation abnormalities may persist on the skin. Complications of EAI include malignant degeneration, which should be closely monitored.

How to prevent Erythema Ab Igne?

To prevent erythema ab igne, you must stay away from prolonged exposure to heat sources.  Do not sit to close to fires, wood stoves, or space heaters.  If you use water bottles for injuries, limit the amount of time that a water bottle is used.  Try not to place a laptop on the thighs when working as this can cause the thighs to have exposure to heat.   The underside of laptops is often 50 degrees C or higher, which many do not realize. Heated seats should not be used in vehicles all the time.  If you must use a heated seat, only use it until your body has warmed up enough and then switch it off.  If your job requires you to be close to an open heat source, such as a chef or a blacksmith, wear protective clothing so the skin is not exposed to the heat and take frequent breaks.


Reference Sources:

1. Medical Dictionary

1 reply
  1. anni
    anni says:

    All my life I have dealt with this strange condition. Whenever I decide to sunbathe, within 10 minutes, blotchy redness starts to form (most commonly on my thighs, neck, and shoulders). I’ve never experienced Erythema Ab Igne with the common causes of excessive contact with heaters, laptops, or other heated objects. Only during the Summer and places/ days with a high UV index. Along with Erythema Ab Igne, I also experience prickly heat. Right before the lacy patterns appear, the tingly sensation associated with prickly heat (also referred to as miliaria or simply as a heat rash) occurs. Not long after the visible symptoms of Erythema Ab Igne appear, the prickly sensation and heat become unbearable and I quickly find shade. Usually in about a minute without sun exposure, the blotchiness fades along with the tingly sensations. While the visible symptoms seemingly disappear, I am left with an intense itch covering my entire body for what seems like hours. I’m not sure if this is to be associated with Erythema Ab Igne, prickly heat, or maybe something entirely else, but whatever it is, it sure is annoying.


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