Thank you @colleenyoung

The accidental discovery happened when I was using an inversion table for traction. I have occasional sciatica from a lumbar disc issue decades ago. When I get some foot pain caused by the sciatica I use the table for some traction relief. Coincidentally I was also suffering with a bout of forearm itching when I got on the table. When I finished the 15 minute session. The foot pain was almost gone but so was the arm itching. I realized they were similar issues and within a couple of days developed a simple neck traction exercise. So I added it to a daily morning stretching routine and the itching has stayed away ever since. If I occasionally feel itching coming the traction exercise takes my itching away in minutes.

The exercise is simple: While standing, I take my shoulders and roll them back and hold them down. Then I lift my head off the shoulders using my neck muscles. I hold that position and count to 30 slowly. Then I do my usual stretch of touching my toes for the same 30 seconds. I return to my first stretch of shoulders back and down while lifting my head off my shoulders and holding for 30 more seconds. I repeat this series 3 times.
Since starting this stretch a couple of years ago I've increase my stretch times to 60 seconds from 30 seconds.

This stretch has helped me but I sure there are levels of the Brachioradial pruritus condition. I hope this helps some of you.