The itchiness that comes with some annoying dermatological conditions might be caused by certain microbes on skin. In a study published November 22 in the journal Cell, a team of scientists found that a common skin bacterium called Staphylococcus aureus can result in itchiness by acting directly on the nerve cells.
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This is the first time that scientists have observed how this microbe works to create itching sensations. The finding adds an important piece to the puzzle of why some common skin conditions like eczema often have a persistent itch. Eczema, also called atopic dermatitis, affects about 20 percent of children and 10 percent of adults in the United States. It usually causes the equilibrium of microorganisms that keep our skin healthy to be thrown out of balance. These conditions allow S. aureus to flourish, according to the study’s authors from Harvard Medical School.
Previously, dermatologists believed that the itchiness that accompanies eczema happened because of skin inflammation. The new paper shows that S. aureus causes itch by beginning a molecular chain reaction that ends in the urge to scratch the skin.
“We’ve identified an entirely novel mechanism behind itch—the bacterium Staph aureus, which is found on almost every patient with the chronic condition atopic dermatitis. We show that itch can be caused by the microbe itself,” study co-author and dermatologist Isaac Chiu said in a statement.
In the study, researchers exposed the skin of mice to S. aureus. Over several days, the animals developed an intensifying itch. The repeated scratching caused worsening skin damage that eventually spread beyond the original site of exposure.
The mice exposed to S. aureus also became hypersensitive to unharmful stimuli that would usually not cause the skin to itch. They were also more likely to develop abnormal itching in response to a…
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