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Scratching an itch does indeed just make it itch more

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Well that's settled. You know how your mom always told you not to scratch that mosquito bite because that just makes it itch more? Your mom was right, and now we have the science to prove it.

A team of heroic scientists at the Washington University School of Medicine in St. Louis just published a study in Neuron confirming the old wives' tale. Turns out the biology behind the phenomenon is rather simple. And sort of surprisingly involves serotonin, the happy hormone.

Zhou-Feng Chen, the director of the school's Center for the Study of Itch, describes it well, "First you scratch, and that causes a sensation of pain," says Chen. "Then you make more serotonin to control the pain. But serotonin does more than only inhibit pain. Our new finding shows that it also makes itch worse by activating GRPR neurons through 5HT1A receptors."


Those complicated looking acronyms basically refer to the way that the nerves throughout your body communicate with your brain. Scientists figured out that these neurons and receptors were involved by doing itch tests on two sets of mice: one normal group and one group that couldn't produce serotonin. When they injected an itchy chemical into their skin, the ones without serotonin simply didn't scratch as much. Crazy, right?

Well, this information is also useful. If you get a mosquito bite or poison ivy or whatever, don't scratch it. Smear anti-itch chemicals all over it instead.


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