SCRATCHING’S SO CATCHING!

AN IMAGE of someone scratching, or of fingernail marks on the skin, or of something that triggers an itch, for instance head lice, can prime our body to notice the ‘itchy’ signals that happen all the time on our skin but that the brain would mostly ignore.

This stimulus makes you likely to scratch, too.

And it’s not just psychological: U.S. scientists from Washington University School of Medicine in St Louis recently discovered that the sight of someone else scratching actually causes the release of a chemical in the brain that communicates itch signals from the skin to the spinal cord.

Where you scratch in response to an image depends on the health of your own skin — people with skin conditions such as dermatitis scratch in different places from the person they’re watching, while those with healthy skin scratch in the same place as that person.