Why do I get this specific itch?

http://allergies.about.com/od/urticariahives/a/dermatographism.htm

Try rubbing a spoon handle gently on your arm and thigh. I can play tic-tac-toe on my skin. Little red weals come up and itch, altho I am much better since I changed diet (no animal protein, little or no dairy.) I used to take Zyrtec (antihistamine daily) but have stopped.

There are also neurological issues that can cause various sensations – I have an compressed nerve that creates a sensation of running water on the outside of my thigh. The only way to deaden the nerve is capsacin cream.