If Your Hand Itches, You Can Scratch Your Other Hand.

This only applies to people who have a condition in which they cannot scratch an itch, such as an injury or skin condition (otherwise, just scratch it), but one new, albeit small, study offers an interesting way to relieve itching in an arm or leg. … when you can’t scratch: stand in front of a mirror and scratch the opposite limb.

So if your left hand itches, look in the mirror and scratch your right hand instead. It might sound silly, but it can actually relieve the itch, according to a study published in its entirety on PLOS One (which you can read at the link below). The researchers conducted a couple of experiments in which they artificially injected histamine into a subject’s body. hand to itch, then bring them to a mirror and ask them to scratch the opposite limb instead of the one they injected. Results:

In both experiments, scratching a non-itchy limb significantly and selectively attenuated the perceived intensity of itching in the mirror-like state, that is, when the non-itchy forearm was visually perceived as an itching limb.

In fact, even though they knew they were not scratching an itchy limb, as long as the visual illusion persisted that they were scratching a itchy hand, thus relieving itching. However, this visual illusion is important, and if the participants knew, even through the illusion, that they were not scratching their right hand, it would not work. Researchers say in the study:

The current study tested the hypothesis that “specular scratching,” that is, scratching a specular, non-scratching forearm, can relieve limited experimentally induced itching. In line with our hypothesis, we observed a significant reduction in pruritus due to remote scratching only under experimental conditions in which the participant visually perceived the scratching of the forearm as an itchy forearm. Observing scratching of a non-itchy forearm without visual illusion did not result in amelioration of itching.

It is important to note that the groups of participants here were rather small (26 men aged 19–38 in the first experiment, the number of which was reduced to 20 after adjusting for experimental variables), and this was experimentally induced itching. Suffice it to say that your experience may be different if you decide to try it yourself. On the other hand, you really have nothing to lose by trying to fool yourself in this way other than, well, continuing to itch, and if you can fool yourself, you just might find relief.

Removing itching with a mirror scratch. Psychophysical Research | PLOS One via Discover magazine


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