AN itchy ankle is the most pleasurable body part to relieve by scratching, an international scientific study has found.

Volunteers were made to itch by their skin being rubbed with cowhage, a plant so irritating to us that it is known in parts of Africa as the mad bean.

The research found that scratching an itch on the ankle, when compared with an itch on the forearm or a hard-to-reach itch on the back, was the most pleasant.

Here FRANCIS McGLONE – professor of cognitive neuroscience at Liverpool John Moores University and a member of the International Forum For The Study Of The Itch – explains why the research is so important.
I COME from a background in pain research and I know that chronic itching, like chronic pain, devastates lives.

We have known for some time about a system of nerves in the skin called C-fibres which convey pain messages to the brain. But it was only just over ten years ago that Professor Martin Schmelz, of Heidelberg University, discovered the body has a similar system for skin itches.

Knowing there are specific nerves for itch has allowed medical research to target drug therapies to try to stop itch nerves working in chronic conditions such as psoriasis and eczema.

A chronic itch is one that doesn't go away by scratching. Sufferers receive no sympathy — they are more likely to be laughed at. But you cannot ignore an itch. It is overpowering.

When we relieve an itch by scratching it we feel pleasure — there has to be a good evolutionary reason for this.

Sex is pleasurable to encourage us to reproduce, eating is pleasurable to encourage us to feed. Scratching an itch is probably pleasurable because we are far more likely to do things if they are enjoyable, so the pleasure of scratching ensures we attend to the itch's source, such as a parasite.

The ankle may be the most pleasurable area because our bare feet were the most exposed to fleas in grasses. But why is scratching so rewarding it can make chronic itch sufferers scratch until the skin bleeds?
If you scratch your arm for no reason, it is a bit painful. But if you do it to ease an itch, it's pleasurable.

We are learning more about the science behind itching — but there is still a long way to go.