Why do we itch? what happens in our body that makes us itchy?

Itch: Itch is the need to or desire to scratch. Receptors in the skin transmit sensation to the brain or spinal; cord. There is actually a scratch reflex simialr to a pain reflex ( you get stuck with a pin and jump). Histamine is a chemicla releaed by cells in response to certain stimualtions, histamine cause local itchy response by stimulating nerve fibers. Mechanical irritation also stimuates these.