Itching could soon be relieved for millions of people by shining a light on the skin, scientists claim.
Tests on mice showed they no longer experienced the annoying sensation after undergoing the treatment – and they scratched less.
The results, which have been branded ‘exciting’, give new hope for those who suffer with chronic skin disorders such as eczema and psoriasis.
Itching could soon be relieved for millions by shining a near-infrared light on skin that has been treated with a chemical, exciting results from a study in Rome have found
Itchy skin is a major symptom that many patients battling the conditions would describe as annoying or even life debilitating.
However, the relief of scratching an itch is only temporary, as it can cause the skin to be damaged further, creating a vicious cycle.
Current treatment options for relieving itchy skin relies, most often, on controlling the skin’s barrier and inflammation with creams and moisturisers.
This doesn’t target the itch itself, and what drives a chronic itch at a cellular level is not fully understood – despite years of research.
Researchers at the European Molecular Biology Laboratory in Rome set out to target the root cause of the itch, in hope of a new treatment.
They developed a chemical, called IL31-IR700, which is sensitive to light and binds to itch-sensitive cells in the surface of the skin.
The team injected this chemical into the skin of mice. When the chemical-treated skin was illuminated with near-infrared light, the cells which sense itch retracted from the surface of the skin, tests showed.
This made the tingling sensation of the itch stop, the researchers wrote in the report published in the journal Nature Biomedical Engineering.
Dr Paul Heppenstall, study co-author, told MailOnline: ‘The infrared light activates a molecule called a photosensitizer which zaps anything in very close proximity to it.
‘As a result, when the photosensitizer is on the surface of the itch neurons, it clips off their endings so that they can no longer detect the itch.
‘The process is called photodynamic therapy and was originally developed to kill cancer cells.
‘By applying it in the skin in a very directed fashion we can selectively ablate the neurons which are causing the itch – much like performing microsurgery using light.’
To the delight of the researchers, led by Dr Linda Nocchi, the method worked well in mice with eczema.
They found it also benefitted the rodents with a rare genetic skin disease for which there is currently no cure – amyloidosis.
Amyloidosis describes a group of rare conditions which occur when a substance called amyloid builds up in the organs.
It can affect a list of organs including the heart, kidneys and liver. However, cutaneous amyloidosis effects the skin in a similar way to eczema.
Other types of nerve cells in the skin which allow you to feel sensations such as pain, vibration, cold or heat, were not affected by the light treatment.
The effect of the treatment lasted several months, suggesting this could be a long-term fix for people who have difficulty finding treatments.
‘For me, the most exciting part of this project was seeing the improvements in the animals’ health’, said Dr Nocchi.
‘Their skin looked much better after treatment and they scratched less.’ The researchers now plan on testing the method on humans.
Dr Heppenstall said: ‘We hope one day, our method will be able to help humans suffering from a disease like eczema, which causes chronic itching.’
Because the team would need to test what the long term effects would be, both for effectiveness and safety, a treatment for humans wouldn’t be available for at least ten years, Dr Heppenstall said.
In April, the same group of researchers published a method to manage chronic pain with light in a similar way.
The team injected the affected skin area with the chemical and illuminated it with near-infrared light. The targeted nerve cells retracted from the skin’s surface, leading to pain relief.
‘We think that the mechanism we’ve discovered might be a general method for controlling sensation through the skin,’ Dr Heppenstall said.
Worldwide, about 20 per cent of children and up to three per cent of the adult population have some form of eczema.
‘Our goal now is to take these therapies further. We want to collaborate with industry partners to develop therapies for humans, but also for veterinary medicine, as itch is a major problem in dogs as well.’