Why is it, when someone talks about e.g. their cat has fleas, do we suddenly feel the urge to scratch a previously nonexistent itch? Are we just becoming hyper aware of pre-existing itches or is it all in the mind?
I very much suspect the latter, based on personal experience.
It was definitely the latter when I read your post. I know because I was vaguely aware of the sensation, but only felt the need to scratch it after you said something. And I’ve had this experience before that.
It seems to be hard-wired into our physiology.
That might address your question, which seems more about sympathetic itching than psychosomatic itching, by your description.
Not relevant, but there is a peer reviewed medical journal titled Itch. Itch