Any swelling, redness, change in appearance of your nipple/areola, akin "puckering", or discharge from the nipple? Because not knowing if something is wrong or not brings such anxiety, I would recommend that you see your GYN and get a mammogram. A mammogram is the best diagnostic test we have at the moment, but it can still miss up to 10% of all cancers. Read about inflammatory breast cancer (IBC) not to scare yourself, but to inform yourself so that you can be very assertive with your doctor.
Please let us know what you find out and I am sorry that you are having problems with this intense itching. It must be terrible. Hugs, Laurie