Toasted skin syndrome and other hot water bottle safety risks when trying to stay warm

Hot water bottles come with certain health risks. (Getty Images)
Hot water bottles come with certain health risks. (Getty Images)

The last year has left us in a bit of a pinch thanks to the ongoing cost of living crisis and energy price jumps. This has left many of us scrambling for economical ways to keep warm, from investing in cosy blankets to reaching for our trusty hot water bottles.

But snuggling with one on your lap for hours on end while you work from home actually comes with some health risks, including the threat of ‘hot water bottle rash’ or ‘toasted skin syndrome’.

This is a skin condition caused by long-term exposure to heat, for example having a hot water bottle lying on your tummy for hours on end.

"When people over-expose their skin to heat radiation from a hot water bottle, they can get a mottled, red rash which is commonly referred to as toasted skin syndrome," explains aesthetic physician, Dr Andre Brittain-Dissont.

"The actual medical term is 'erythema ab igne', which means 'redness from fire' in Latin. The rash itself can look red to brown in colour, almost like sunburn or prickly heat and may be itchy."

Toasted skin syndrome treatment

Dr Brittain-Dissont explains that the best treatment is reducing the amount of time you expose your skin to a hot water bottle but if the rash persists, he suggests seeking medical help or asking a pharmacist for a hydrocortisone cream.

And if symptoms continue do visit your GP who will likely prescribe topical medications such as retinoids which can help.

Stock picture of hot water bottles, which can go out of date. (Getty Images)
Hot water bottles can go out of date. (Getty Images)

Thankfully, if you've become quite attached to your hot water bottle of late, there are also some things you can do to avoid toasting your actual skin.

"If you’re using heating pads or heated blankets, it’s best to have a clothing barrier between the heat source and the skin," advises GP Dr Ross Perry, medical director of Cosmedics.

"Keep heat levels moderate not allowing them to get too hot which also includes hot water bottles – they shouldn't be placed directly on to the skin and should never be boiling."

Other hot water bottle health risks

Nasty skin rashes aren't the only health risk associated with the rediscovering of your trusty warmer.

Believe it or not, a hot water bottle can actually go out of date and there can be some pretty serious consequences if it has expired.

Dr Hilary told ITV’s Lorraine in 2022 that hot water bottles are only designed to last up to three years from manufacture.

Although some manufacturers recommend that you use it for no more than two years, so it is important to check when you buy one.

Turns out old bottles can degrade over time and eventually split, which can be pretty nasty considering they are often filled with near boiling water.

How to tell when a water bottle has expired

Thankfully, Dr Hilary revealed a quick and easy tip for checking whether your hot water bottle is still in date, urging consumers to remove the cover to check the bottle itself.

"When it's really cold a hot water bottle is a good way of keeping warm in bed or on your lap," he told host Lorraine Kelly. "Inside the funnel of your hot water bottle there's a little floral sign."

Dr Hilary went on to point out that the number inside the floral sign is the year the hot water bottle was made.

"There's a number 19 in this one, so that hot water bottle was made in 2019 and is three years old now, and that is what the manufacturers are saying is the expiry date for most hot water bottles."

The 12 "petals" round the edge of the floral symbol indicate the months of the year and give an even more accurate indication of the bottle's manufacture date.

Stock picture of a woman keeping warm with a hot water bottle. (Getty Images)
Experts are urging people to check the expiry date of their hot water bottles. (Getty Images)

You can tell the month the hot water bottle was manufactured from when the dots end, so, for example, if it has dots in eight segments it was made in August.

Dr Hilary went on to say how important it is to know the expiry date of your hot water bottle because the lid sucker can become loose and the rubber can perish and you can get scalded.

"So they're saying you need to check the date on your hot water bottle."

Don't put boiling water in your hot water bottle

The warning comes after Alice Beer issued a similar call to action for hot water bottle fans.

Speaking on This Morning in 2022, the consumer expert revealed that she had been approached on Instagram by a mum of a 15-year-old who had been revising and cuddled close to a hot water bottle.

The teenager had put boiling water in it, which Beer strongly advises against, and as the hot water bottle had a cover over it, she didn’t notice that it had perished and received third degree burns on her stomach and legs, resulting in a hospital stay.

“Half of hot water bottle injuries need skin grafts and surgeries," Beer said.

"These are not surface burns, these go really deep.”

Beer also went on to urge everyone to remove the cover of their hot water bottle and look out for the symbol which reveals the manufacture date – and therefore the suggested expiry date.

Stock image of a woman filling a hot water bottle. (Getty Images)
Experts are also warning not to fill your water bottle with boiling water. (Getty Images)

Other ways to stay safe when using a hot water bottle

Beer had some other suggestions for staying safe while using a hot water bottle too.

"I’m going to say something really stupid here, but it’s relevant," she continued. "When you buy a hot water bottle, the point is that the rubber is insulating and it’s strong; so if it doesn’t smell rubbery and it doesn’t feel rubbery, then it’s got a higher proportion of additives to rubber.

"So actually what you want is a real rubbery hot water bottle because that will protect you more. If you’re buying a cheap one, it’ll have less rubber in it and is more prone to perishing."

Beer went on to urge people not to put boiling water in the hot water bottle and to always take the cover off before you add the water so that you don’t miss the expiry date.

Following a warning from one of its nurses, who needed a skin graft after being burnt by a hot water bottle, NHS Wales has issued the following safety advice.

  • Fill the bottle with hot, but not boiling water

  • Make sure the stopper is securely screwed on

  • Fill the bottle to a maximum of three-quarters full

  • Wrap the bottle in a towel to prevent direct contact

  • Avoid taking the bottle to bed

  • Frequently examine the bottle for signs of wear and tear

  • Make sure it has been tested to BS1970:2006 standards

  • Expel all air above the water level before sealing carefully, to prevent injury from the escaping hot steam

  • Replace the bottle after two years

  • Special care should be taken when used by those with sensory deficits, the elderly and children

Winter warming: Read more

Watch: Dr Hilary Jones shares hack for checking if your hot water bottle is out of date