Why scratching that itch really does make it worse

Mother was right: scratching an itch really does make it worse.

Research shows that while scratching provides temporary relief, it triggers the production of a brain chemical that makes the itch even more maddening.

Appropriately, the research was carried out by scientists at Washington University’s Centre for the Study of the Itch in the US.

After experimenting on mice, they concluded that scratching initially helps by creating pain. Nerve cells in the spinal cord are kept busy transmitting pain signals to the brain, leaving fewer to tell the brain about the itch.

But when the brain registers the soreness caused by our fingernails scraping across our skin, it releases serotonin.

This is meant to dull the pain but also intensifies the itch, leading to a vicious circle of more scratching, more serotonin being released – and more itching.

It is thought that serotonin has the same effect in humans, raising hope of better treatment for conditions that lead to unbearable itching, including eczema, which affects up to six million Britons, kidney disease and cancer.

Those on Dialysis often suffer severe itching as a result of their kidney failure.

And some cancer patients find their painkillers irritate their skin so much that they have to cut back on their medication

MacRae, F. Daily Mail 31 October 2014, p. 5.

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