can anyone explain what an itch on the body is?
An itch is defined as an irritating or tickling sensation in the skin which may be generalised (all over) or localised (confined to a specific area).
Although itching is a major indicator of many skin diseases and conditions, it does not necessarily (of itself) mean that there is anything wrong.
The mechanism is not fully understood (so I believe, at least not in any of my references).
From an evolutionary POV, I would suggest that the irritating nature of the sensation encouraging the sufferer to scratch or slap at the source is associated with the feeling of an insect or parasite crawling on the skin. This makes the target aware of the potential attack and the automatic response helps to keep him (relatively) free of bites and infections.
The fact that an itch can arise from no obvious cause may only signify that the early-warning system is not perfectly designed (like much of the human body), and is liable to give false readings or to react to events below the normal threshold. This is to be expected from a system built by trial and error.
Hi, funguy, and welcome to the SDMB. I searched in GQ going back 2 years and found several threads dealing with what itches are, what causes them, and so on. Here are some of the better results I found:
http://boards.straightdope.com/sdmb/showthread.php?threadid=94626
http://boards.straightdope.com/sdmb/showthread.php?threadid=73906
http://boards.straightdope.com/sdmb/showthread.php?threadid=55053
http://boards.straightdope.com/sdmb/showthread.php?threadid=52955
http://boards.straightdope.com/sdmb/showthread.php?threadid=51989
Hope this helps.
I didn’t see anywhere in those posts that mentioned why a certain area became itchy. When it was the back, why not the arm, or why not the stomach?
And, we sort of know what it is, but what causes it to occur in the first place?
All I saw was the issue addressed after the fact, not from stage one.