Why that constant itch could be a sign of kidney disease, poor liver function, thyroid problems – or even cancer

For more than fifty years, Martyn Pring’s life was dominated by an ‘uncontrollable’ urge to itch – and nothing doctors suggested seemed to help.

It started after a bout of German measles when he was two, and from then on Martyn, now in his sixties, was regularly overcome by the urge to scratch his skin until it was raw and bleeding.

The sensation affected every part of his body except his face, regularly interrupting his sleep, and even as an adult he had to wear mittens to bed to try to stop his incessant scratching.

‘I’ve tried every emollient cream [medical moisturiser]lotion and medicine out there, but nothing worked,” says Martyn, a university researcher and author, who lives with his wife in Swanage, Dorset.

‘I spent two weeks in hospital with itching more than once.

‘I was covered in bandages and bathed in soothing creams [medical moisturisers] and I was so tightly bandaged that I had to stay in bed.

“But the itching always came back.”

It was in 2018 – more than fifty years after the itching, diagnosed as eczema, started – that his dermatologist Martyn suggested he do a clinical trial of a new treatment called dupilumab (brand name Dupixent). This treatment can be given to patients whose eczema has not responded to other treatments, and works by preventing the immune system from overreacting, thereby reducing inflammation.

For Martyn, the injections he now receives every two weeks from his GP have ‘changed my life in a way I can’t describe’.

“No one knows how excruciating chronic itch is until you go through it,” he adds.

About one in six (17 percent of us) are plagued by a general itch (all over the body, rather than in one spot) without an obvious skin condition. This figure is believed to be as high as half of older people, according to the Association for Primary Care Dermatology.

The causes range from allergies to liver or kidney problems, diabetes and in rare cases cancer.

Last year, scientists from Harvard Medical School discovered that a common microbe that lives on the skin – Staphylococcus aureus – could be responsible for persistent itching in people with skin conditions such as eczema.

Their research, based on animal studies, found that the microbe, which normally lives harmlessly in about 30 percent of people, can be found in higher amounts in some people with eczema. They release a chemical, protease V8, which activates a protein (PAR1) on the skin nerves: once activated, it sends signals from the skin to the brain, resulting in the urge to scratch.

Conditions such as eczema, hives and psoriasis also cause inflammation, which leads to the release of chemicals by immune cells known as cytokines. They recruit other immune cells to the spot, triggering nerve cells in the skin to send a message to the brain, causing an itchy sensation. , explains Dr Haytham Al-Rawi, consultant dermatologist at University Hospitals Birmingham NHS Foundation Trust.

For people who don’t have a skin condition, the most common cause of itching is dry skin, explains Dr Elise Kleyn, consultant dermatologist at Salford Royal NHS Foundation Trist and spokesperson for the British Association of Dermatologists.

That’s because dry skin is due to a compromised skin barrier, making it prone to irritation, she says.

Some women also feel like their skin is itchy during and after menopause because the drop in protective estrogen levels can make the skin drier.

Whatever the cause, there’s a good reason not to scratch an itch because the more you scratch, the more you irritate the skin, making it even more itchy.

“This is known as the positive feedback cycle,” says Dr Al-Rawi. Instead, he recommends applying something cool to the area. (Cooling works on certain nerve fibers and encourages them to send soothing signals to the brain.)

The risk is that scratching can make the problem chronic because the nerves can become hypersensitive, so that “something that doesn’t normally cause itching, such as pressure or touch, can trigger a reaction and cause generalized itching,” says Dr. Al-Rawi .

Alison MacColl agrees with this. The mother-of-two developed a nasty itch around the arch of her left foot after the birth of her daughter Iona – and 12 years later she still has the itch in the exact same spot.

At first she assumed it was heat related since it was summer. “I was so busy concentrating on my baby that I didn’t think much about it,” recalls Alison, 57, an aromatherapist who lives with her husband Alistair, 57, a lawyer, their daughter Iona and their ten-year-old son. , Angus, in East Kilbride in Scotland.

Alison admits that her scratching made matters worse: the skin on her foot turned red and a blister the size of a golf ball formed. “It kept itching until the blister burst,” she says.

When the worsening cycle continued for a year, Alison went to her GP, who prescribed an anti-fungal cream, which made no difference.

Over the next few years, she returned to her doctor three times.

She was given antihistamine cream in case it was caused by an allergy, and a hydrocortisone cream (which contained steroids) – neither helped. Finally, a stronger hydrocortisone ointment proved effective, and she now uses it sparingly for flare-ups.

The cause of Alison’s itching has yet to be determined, but it appears to be a simple case of jock itch, but that’s not always the case. Generalized itching without a skin condition “may indicate an underlying problem, such as kidney disease or liver problems, and should therefore be investigated,” says Dr Al-Rawi, who is also a consultant dermatologist at Spire Little Aston Hospital.

Kidney problems lead to itching because waste products build up in the blood, irritating the nerve endings and causing the ‘itch response’. In addition to anemia, fatigue and nausea, unexplained itching can also be a sign of kidney failure, says Dr. Al-Rawi.

Itchy skin can also indicate a poorly functioning liver, he adds. As the liver struggles to remove bile salts from the blood, they build up under the skin, irritating the nerve endings.

This may be due to liver disease or may also occur in the later stages of pregnancy when the liver may not be working as well as normal.

Your doctor may suggest blood tests to rule out these or other itch triggers, such as iron deficiency anemia, thyroid problems and celiac disease (an autoimmune disease with symptoms caused by eating gluten), but it’s not entirely clear how these cause itching.

A blood test can also be used to diagnose diabetes, which can cause itching because high blood sugar levels make nerve endings more sensitive.

Medications, such as opioids (morphine and codeine), can cause itching, possibly because they cause too much histamine to be released. The chemical then attaches to mast cells, causing blood vessels to expand and the surrounding skin to itch.

Itching can be a symptom of cancer of the blood or lymph nodes – caused by irritation of the nerve endings by the cytokines released by the immune system in response to the cancer. ‘Usually there will be other symptoms, such as weight loss and night sweats,’ says Dr Al-Rawi.

People with anxiety or obsessive-compulsive disorder may also experience itching, presumably due to a habit or coping mechanism for stress.

Although itching due to a specific medical condition can be relieved by treating that condition, it can be challenging to treat itching if no underlying cause is found, says Dr. Al-Rawi.

Moisturizers are the first line of treatment – the next step is steroid creams and antihistamines (the chemical histamine is released when inflammation occurs on the skin, causing the itchy feeling).

Light therapy – in the form of exposure to UV light in a cabin for a few minutes three times a week for about ten weeks – can work because ultraviolet light calms the immune system and reduces the inflammatory response.

Sometimes certain antidepressants, such as amitriptyline, are prescribed in low doses because they reduce the sensitivity of the nerve endings.

If persistent itching significantly affects a person’s quality of life, immunosuppressants such as methotrexate or cyclosporine may be given, and the last resort – due to cost – are biologics that target the immune response, such as nemolizumab.

‘These new therapies are very expensive, but they are the future of medicine – they have revolutionized the treatment of psoriasis, they help people with eczema and hives, and are said to have helped with general itching,’ says Dr. Al-Rawi. They work by targeting specific pathways of the immune system, reducing the inflammatory process at an early stage.

Researchers continue to search for new treatments. A new immunotherapy treatment for severe atopic dermatitis and eczema, nemolizumab, which blocks the protein Interleukin-31 (IL-31), is being tested in Britain. IL-31, which is normally released by the immune system to fight disease-causing organisms, causes both the urge to itch and skin inflammation when we get itchy.

But can itching sometimes be a good thing?

There’s certainly a reason why some people enjoy a good back scratch: it triggers the release of feel-good hormones like serotonin, says Dr Bernard Ho, consultant dermatologist at St George’s Hospital in London and spokesperson for the British Skin Foundation.

Itching around a scar after surgery can be a positive sign, indicating that the nerves are regenerating and therefore starting to heal.

As for Alison, her itching still comes and goes, but she has managed to identify certain triggers, including alcohol and chocolate.

‘I suffered from flare-ups after eating chocolate eggs at Easter. Some people might get spots on their faces from chocolate, but I get itchy feet.

“But luckily I’ve learned to control it.”

Additional reporting: Julie Cook