advertisement
advertisement

Study Confirms: Stop Scratching, You’re Only Making It Worse

The same chemical that helps people manage pain and depression could heighten the sensation of itching.

Study Confirms: Stop Scratching, You’re Only Making It Worse
[Photo: Flickr user Ben Grantham]

It’s not in your head: Scratching that itch will make it worse.

advertisement
advertisement

Confirming Mom’s advice, scientists at Washington University School of Medicine in St. Louis found that scratching releases a neurotransmitter from the brain called serotonin, a chemical messenger that helps control pain and can exacerbate the sensation of itching. Serotonin also has effects on growth, aging, bone metabolism, and mood regulation. Antidepressants, such as Prozac and Zoloft, help increase serotonin levels to counter depression.

Zhou-Feng Chen, director of the school’s Center for the Study of Itch, said scratching has been known to create a mild pain in the skin, which can result in nerve cells carrying pain signals instead of itch signals to the brain. The brain responds to those signals by releasing serotonin.

“Scratching can relieve itch by creating minor pain,” he said. “But when the body responds to pain signals, that response actually can make itching worse.”

To study the effects of serotonin, the researchers bred mice without genes that produce serotonin and injected them with a chemical that makes the skin itch. Compared with normal mice, those unable to produce serotonin didn’t scratch as much. However, when researchers injected serotonin into the genetically altered mice, they scratched as normal mice would. The study appears in the journal Neuron.

In addition, the scientists say it’s possible to disrupt communication between serotonin and nerve cells called GRPR neurons in the spinal cord. They confirmed a specific receptor called 5HT1A helps activate the GRPR neurons by treating mice with a compound blocking the receptor. Those mice also scratched much less than their normal counterparts.

“First you scratch, and that causes a sensation of pain,” Chen said. “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.”

advertisement

The researchers’ best advice: Try as hard as you can not to scratch.

advertisement
advertisement

About the author

Based in San Francisco, Alice Truong is Fast Company's West Coast correspondent. She previously reported in Chicago, Washington D.C., New York and most recently Hong Kong, where she (left her heart and) worked as a reporter for the Wall Street Journal

More