To scratch an itch is a hairy problem

An insect lands on your arm, moving the tiny hairs on your skin just enough to make you want to scratch. Researchers have shed light on why light brushing movements like this on our hairy skin make us scratch. Surprisingly, the spinal neurons involved in the tingling sensation caused by a light touch are different from those transmitting pain or a 'chemical' itch, the latter elicited by a mosquito bite or a skin wound that is healing.
Source: ScienceDaily Headlines - Category: Science Source Type: news