A dermatologist has warned people against keeping a portable heater under their desks when working. The advice was shared by Dr Abigail Waldman, MD FAAD, a Board Certified Dermatologist and Harvard Associate Professor.

Known as Dr Abby on TikTok, the doctor often shares informative videos with her 521k followers under the handle @Drabby6. In one recent post, the expert shared a video titled: "Three things I would never do in the winter as a dermatologist." In the footage, Dr Abby explained that she would never store a heater close to her legs under her desk.

Dr Abby also said she would not make her bed right after waking up, or use a tanning bed. She told followers: "So the first is I would never use a space heater under my desk, really close to my skin, because it can result in this.

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"This rash is erythema ab igne (EAI), and it is really difficult to get rid of once you get it. It is from chronic heat exposure close to the skin, such as a space heater, a hot water bottle, or even putting your laptop on your lap."

Dr Abby continued: "The second thing I would never do as a dermatologist in the winter as someone who has a dust mite allergy, I would never make my bed right after waking up. Those dust mites love a warm, comfy hot be when you put that cover back over when you make your bed in the morning."

EAI or 'toasted skin syndrome', is a skin condition marked by a reddish-brown rash and hyperpigmentation. According to DermNet, it can be caused by sitting too close to open fires and electric space heaters.

The website explains: "EAI is a skin reaction caused by chronic exposure to infrared radiation in the form of heat. It was once a common condition seen in the elderly who stood or sat closely to open fires or electric space heaters. Although the introduction of central heating has reduced EAI of this type, it is still found in individuals exposed to heat from other sources."

These other sources could include repeated exposure to car heaters or furniture with built-in heaters or the repeated application of hot water bottles to treat chronic pain, DermNet added.

Symptoms could include a mild, red rash from limited heat exposure or marked redness from prolonged, repeated exposure. Some patients could also experience itchiness and a burning sensation. Always speak to a GP about any health concerns.

Early stages may be blanching red; with time, it becomes fixed, dark, and may involve skin thinning (atrophy). Quickly stop or significantly reduce heat exposure.

It usually gets better over weeks to months after the heat is taken away, but the colour change might stay. A biopsy may be necessary to check for other issues or early signs of cancer if the rash doesn't get better or looks different.