Hello,
You mean to say brachioradial pruritis (BRP). The main cause of BRP is not known but there is evidence to suggest that BRP may arise in the nervous system. BRP may be attributed to a neuropathy, such as chronic cervical radiculopathy.
Get it evaluated from a dermatologist.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.