I’ve often wondered what an itch is and how exactly they work. No, really; I have. Luckily for me, then, researchers from the Salk Institute for Biological Studies have helped elucidate the mechanism a little in a paper published in Science (paywall). They engineered mice that did not have a certain type of sensory neuron that creates a chemical signal called neuropeptide Y. The mice turned out to be extremely sensitive to mechanical itches, the kind that would be stimulated by a bug or annoying piece of fluff landing on you. They were so sensitive to stimulus that they created bald patches from itching so much yet they reacted normally to pain and chemicals that would normally make them itch. This suggests that there is a distinct pathway for the suppression of mechanical itch.
It is through small, incremental breakthroughs like this that most science is done. Now that they have a foothold, these and other researchers will be able to delve ever deeper into the various mechanisms that underly the phenomenon. Why does any of this matter? Because there are people out there who suffer from conditions such as alloknesis and allodynia that are desperate for relief and this work might be the basis for some future treatment years down the line. It’s also just plain interesting. Maybe these cells are part of the mechanism that stops us being driven insane by constantly noticing our clothes brushing against us? Maybe they’re not. We’ll never know unless we keep looking though.