Scientists may have put their finger on what makes us itch – they’ve pinpointed a chemical that tells the brain about the maddening sensation.
Without it, there’s no impulse to itch – and therefore no scratching.
The breakthrough by the U.S. government’s health research arm offers hope of new treatments for conditions that cause severe itching, including eczema.
Others that could benefit range from cancer patients to people on kidney dialysis.
The team from the National Institutes of Health in Maryland tested a range of chemicals that carry information to the brain to find out which were essential to the perception of itchiness.
This led them to a key compound called Npbb – and they showed that mice that can’t make it don’t itch.
Lead author Santosh Mishra said: ‘When we exposed Npbb-deficient mice to several itch-inducing substances, it was amazing to watch.
‘Nothing happened. The mice wouldn’t scratch.’
However, if the creatures were injected with Npbb they started to scratch.
Further research established the chemical as an essential first step in the process that transmits information about itchiness to the brain.
Likely beneficiaries include eczema sufferers, as well as diabetics and liver patients, who are often overcome with the need to scratch.
Kidney dialysis patients can suffer severe itching, while some cancer patients find their painkillers irritate their skin to such an extent that they have no option but to cut back on the medication.
In addition, the damage done by constant scratching can lead to infections in patients who are already very ill.
However, with Nppb also having other important roles in the body, it wouldn’t be safe to simply create a drug that stops it from working.
Researcher Dr Mark Hoon said: ‘The challenge is to find similar biocircuitry in people, evaluate what’s there and identify molecules that can be targeted to turn off chronic itch without causing unwanted side-effects.
‘So this is a start, not a finish.’
Previous research has shown why it feels so good to dispatch an itch.
Brain scans revealed that scratching numbs the part of the brain linked to unpleasant thoughts and memories.
It also ramps up activity in regions linked to compulsion – perhaps explaining why we sometimes can’t help but scratch and scratch and scratch.
Attribution: Fiona Macrae, Mail Online