Does scratching release some sort of chemical or does just the sensation of a scratch override the sensation of an itch temporarily and has nothing to do with eliminating an itch?
Curious today.
Door #2. My understanding of it is that the body cannot register more than one sensation at a given location, so scratching creates minor pain that overrides the itch. I’m sure someone will be along soon with a more technical explanation.
If that’s the case, then why does the itch usually (I say that carefully) go away after a scratch.
As an afterthought, any chance that the scratch serves more than one purpose?
I believe the current theory is that an itch is localized low-level pain signals, a bit like skin static. A bad comparison is to buzzes and blurs you see in the dark- the nerves are straining to pick up any signal, so they boost their inputs. That’s also why an itch tends to get worse over time, or move, or multiples itches spring up. It’s true biofeedback.
Scratching disrupts the cycle, with a non-low-level signal. I think it resets the receptors to normal.
jb,
suddenly feeling itchy.
p.s.- don’t yawn.
Of course there’s the more prosaic reason. If something is genuinely irritating the skin (an allergen, a grass spicule, an ingrowing hair, fleas, lice) then scratching will obviously dislodge the irritant.
From britannica.com: