After developing back pain last October, musician Joey Clarkson took that time-honoured step and began using a hot water bottle to ease it while she waited for an appointment to see her GP.

‘The pain was excruciating and came from nowhere,’ Joey, 34, recalls. ‘I hadn’t injured myself so had no idea what caused it.’

The GP referred her for an MRI scan but the waiting list was long — ‘I was told it could be months,’ says Joey, who lives in Bridport, Dorset, with her husband, Peter, 36.

‘I was in so much pain that I started using a hot water bottle every night for relief — and then, even during the day. Heat numbed the pain . . . until the water got cold.’

Because of the long wait, Joey decided to pay to have a private MRI scan. This revealed a herniated or slipped disc, where the jelly-like substance inside it pushes out, pressing on the nerves.

‘Suddenly the pain made sense,’ she says. ‘But I was told surgery would be months away, too. I was in despair, and only my hot water bottle helped me.’

Joey Clarkson started using a hot water bottle regularly to ease her back pain, often placing it in direct contact with her skin

But while it helped with the pain, it caused a red, mottled rash across her lower back. At first Joey ignored it, thinking it would pass, but six weeks later there was no improvement.

In fact Joey’s skin became itchier and the red marks grew darker and more angry.

So she went to see her GP again — and later a dermatologist — who diagnosed her with toasted skin syndrome.

Otherwise known as erythema ab igne (derived from Latin and translated as ‘redness from fire’), this is caused by long-term use of heat directly against the skin.

It leads to a red or brown rash which has a distinct net-like pattern in appearance, as well as itchiness.

It can happen to anyone who is exposed to chronic low-level heat, such as from using a hot water bottle, resting a laptop on your legs, leaning on a radiator or using an electric blanket.

The heat is usually not enough to cause a burn, but enough to damage or cause changes in the superficial blood vessels as well as collagen and elastin protein fibres of the skin, which lead to the distinctive appearance and discolouration.

This skin rash is usually permanent, and can leave you marked for life.

Joey had been blithely unaware of the risks as she waited first for her NHS scan, and then surgery.

She recalls: ‘November came, along with the winter weather, and I still didn’t have my MRI date. I started using the hot water bottle through the day, too, pressing it directly against my lower back, with no clothing in between.

‘I started needing a hotter and hotter water bottle to get the same effect, so I was constantly refilling it with newly boiled water. It was the only way I could get any relief from the pain.’

Six weeks after Joey started using the hot water bottle all day, Peter noticed reddish brown and white blotches appearing on her lower back.

Joey Clarkson developed a mottled rash on her skin with a distinctive net-like pattern

‘I thought they were fresh, from using the hot water bottle,’ she says. ‘But the next day, even after not using the bottle for a few hours, the mottled skin didn’t fade.’ The area was also itchy.

‘After that, the mottled patch got worse and now looked like dark red road maps on my back, from hip to hip. I stopped using the hot water bottle,’ says Joey.

Finally, she saw her GP, who took a look and said he believed it was toasted skin syndrome.

‘I was shocked,’ says Joey. ‘I’d never heard of it and thought using heat was perfectly safe.’ She was worried that only a few weeks of use had caused so much damage to her skin.

‘I was also concerned about skin cancer,’ she says. ‘I googled [the condition] and read that, in some cases, toasted skin can make a person more predisposed to skin cancer. It terrified me.’

Initially the heat causes ‘a mild transient mottled net-like red rash,’ explains Dr Zainab Laftah, a consultant dermatologist in London and spokesperson for the British Skin Foundation.

‘Repetitive heat leads to the degeneration of elastin fibres [which provide structure to the skin] and the skin’s basal cells [which help produce new skin cells]. Destruction of basal cells causes the release of melanin [which is what gives our skin its colour], which results in the hyperpigmentation.

‘With repeated heat exposure, the skin develops a lacy rash with red, white and brown pigmentation,’ explains Dr Laftah.

The skin changes result from repetitive damage to the superficial vascular network and skin cells. The heat exposure also causes inflammation in the skin and dilates blood vessels, which can both result in itching.

‘The underlying skin may start to thin,’ adds Dr Anjali Mahto, a dermatologist based in London.

‘Unfortunately, the skin changes including pigmentation may then be permanent — and while some topical creams and lasers may help improve its appearance, the changes are largely irreversible.’ When it comes to longer-term risks, some studies suggest that the changes in the blood vessels caused by toasted skin can lead to skin cancer in extreme cases, says dermatologist Dr Hamdan Abdullah Hamed, who is currently based in Dubai.

‘The heat causes prolonged and repetitive dilation of blood vessels — in other words, chronic inflammation — which in turn has been associated with tissue injury, and that may contribute to the development of skin cancer.’

He warns that ‘those with thinner or damaged skin, coupled with a genetic susceptibility to skin cancer, as well as those exposed to higher-than-usual levels of UV rays, should take preventive measures’ if they suffer from toasted skin syndrome.

That means, for example, using sunscreen, wearing UV-protective clothing and getting prompt medical advice about any new or worrying skin changes.

‘Toasted skin syndrome can occur in any age group, but data suggests that the incidence in women is higher than men,’ says Dr Laftah.

This is possibly because women are more likely to use hot water bottles for relief from period pain and other menstrual disorders.

As for prevention, Dr Mahto suggests ‘using covers on hot water bottles and laptop cooling pads — like a tray you place between the laptop and your skin; you can buy them online for around £20 — thereby avoiding putting the heat source directly on the skin.

‘Make sure you also have a clothing barrier between the source of heat and the skin,’ adds Dr Mahto. ‘And if you do develop toasted skin, especially if it becomes sore or uncomfortable, it is essential to discontinue the heat exposure immediately.

‘Applying cool compresses and using over-the-counter topical creams containing soothing ingredients such as aloe vera can help alleviate discomfort,’ she adds. ‘If you suspect you’ve caused serious damage, see your GP or a dermatologist as soon as possible.’

After her diagnosis, Joey immediately gave up the hot water bottle, and now takes just ibuprofen for the back pain.

She is still awaiting surgery for her slipped disc. Meanwhile, the angry red marks all over her back are not diminishing.

She uses a standard moisturiser made with coconut oil and a CBD-based cream, which she says helps with the itching, as well as a cream from an acupuncturist said to help with scarring.

‘I had no idea using a hot water bottle for pain relief could put me at risk of skin cancer,’ says Joey.

‘It was scary. I think they should come with a heat warning. I’m still in pain every day but never reach for my hot water bottle any more.’

Scarred skin: Joey Clarkson’s lower back after placing a hot water bottle on it daily

DYNAMIC DUOS: ZINC AND SULPHUR 

Red onions, which contain sulphur, are a good accompaniment for zinc-rich foods such as red meat. Try serving them caramelised with your steak or melted into a lentil-based dahl

The mineral zinc is vital for a healthy immune system, wound healing and bone strength. The zinc in animal sources such as oysters, red meat and poultry is significantly more bioavailable [i.e. our cells can use it more easily] than from plant sources such as beans, nuts and whole grains.

‘Plant sources of zinc also contain phytates — antioxidants which protect our cells, but which can also hamper the body’s absorption of minerals such as zinc,’ says dietitian Orli Rhodes.

‘If you are vegetarian, vegan or eat little meat and seafood, try soaking, sprouting or fermenting beans, legumes and seeds first as this can help reduce their phytate content.’

Canned beans and legumes are also a good bet as their processing and extended storage in liquid reduce phytate content. Eating them alongside foods that contain some sulphur, such as onions, garlic and broccoli, can help your body better absorb important zinc from plant sources.

Try: Lentil dahl (made with onions and garlic); stir-fried broccoli with slivered almonds; brown (or wild) rice with caramelised onions; or a wholewheat bagel topped with light cream cheese and sliced red onion.