What happened to the cat with dry skin? Purrrrritus.

I've often wondered why we scratch itches. If you think about it from an objective point of view, it doesn't make any sense to scratch. If anything, it only irritates the skin more. So why does it feel good? Thankfully, the back page of Scientific American, bringer of useless yet fascinating information, had a short article explaining it. Turns out that the "pruritus" (note quotation marks for fancy Latin name for itching) neurons are separate from "pain" and "rubbing" (note quotation marks for non-fancy non-Latin names for pain and rubbing) neurons. Because of a local inhibitory effect, these neurons trump the pruritus sensors, temporarily relieving the itching sensation. The itching arises in the first place from things like dryness and chemical irritation.

Maybe it could work the other way. We could be treating soreness and pain with poison ivy, or something, if the pruritus sensory neurons can also inhibit the pain ones.

Also, "pruritus" is an incredibly tough word to pronounce. It's like "rural," but harder. I can only imagine trying to say it in French; I think I'd need some Halls afterwards.