Mom knew what she was talking about after all: Scratching really does make the itch worse. Good as it feels, the burst of ecstasy you get from clawing your irritated skin only prolongs a vicious itch-scratch cycle, putting true relief farther out of reach. Our natural instinct betrays us.
But why? Though itch has bedeviled our species (not to mention many other animals) for thousands of years, scientists have just begun to comprehend the physiological mechanisms behind it. Over the past couple of decades, research has shown how scratching taps into our brain’s reward and immune systems, producing a strange mix of pleasure and discomfort that makes it all but impossible to resist.
“You scratch to feel better,” says Brian Kim, a neuroimmunologist at Mount Sinai’s Icahn School of Medicine, “but in doing so, you actually activate immune pathways that are counterproductive.” For most of us, this feedback loop is merely annoying, but it can become debilitating for the 1 in 5 people who suffer from chronic itch at some point in their lives.
What Is Itching, Anyway?
In 1660, a German physician named Samuel Hafenreffer gave the definition of itch (pruritus, in medical jargon) that’s still in use today: an unpleasant sensation that provokes the desire to scratch. It comes about through everything from insect bites and poisonous plants to allergic reactions and skin conditions like eczema.
