What causes an itch . . .

[LewPaper]

. . . and why does a scratch stop it?

[Sqad]

Don't know, but try this.

Itches are caused by the release of certain chemicals depending upon the cause of the itch.......usually it is the release of a chemical called histamine.

Scratching doesn't always cure it , but when it does, then the scratch acts as a counter-irritant.......the scratch is more noticeable then the itch.

[Old_Geezer]

I suspect the signal from the scratch overwhelms the itch signal, and so the brain then ignores it.

[LoftyLottie]

I was told to slap t he itch rather than scratch as the slapping signal does what Old Geezer says without irritating the skin.

[LoftyLottie]

My GP told me that when I was literally covered with a dreadful rash. Try slapping yourself all over!!

[mccfluff]

this post is making me itch

[Ankou]

i bet he did

[emmie]

This sounds daft, but i can guarantee if i am washing up, as soon as i put my hands in the sink to do the dishes, my nose starts to itch, and it drives me mad, its not a reaction to the fact of washing up, but there must be some chemical in the washing up liquid, that literally gets up my nose.