It can be due to brachioradial pruritis. Brachioradial pruritis is an intense itching sensation of the arm usually between the shoulder and elbow of either or both arms. The itch can be so intense that sufferers will scratch their own skin to a bleeding condition.
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.
No cure has been found.The only thing that seems to help most sufferers is the application of ice to the area until the itch is diminished. Other treatments include cooling lotions like those containing camphor or menthol,capsacain or local anesthetic creams,amitriptyline and gabapentin tablets and electrical cutaneous nerve field stimulation.
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.