See title for complete Q - what is the biochemical/electrical/whatever process that produces an “itch” and why does scratching relieve it.
(yes, I am using a bit of topical lidocaine at this time)
The link in the quote below seems to have more info but the full text of the article requires registration and I did not feel like bothering. Still, it seems it might have some answers for you.
Not to ding The Master but Cecil’s article is over 20 years old. The article I linked to above seems to indicate that itching is not really low level pain sensors firing but nerves devoted to itching. Again…I only read the synopsis so perhaps it is all bunk but perhaps this is something Cecil should revisit.