Itching (Pruritis) is caused by an irritant such as bugs, dust, clothing fibers, and hair. It is built-in defense mechanism to alert your body to potentially being harmed.
Once something like hair or dust scratches the surface of your skin’s nerves receptors, the skin becomes irritated.
In a split second, these receptors send a signal through nerve fibers to your spinal cord and then up to the cerebral cortex in your brain where they are actually felt as an itch.
As soon as we feel an itch, we scratch the spot. The reason for this is that we want to remove the irritants as soon as possible.
Your brain realizes that you’ve scratched away the irritant, so the signal being sent to your brain that you have an itch is interrupted.