Intense Arm Itching After Treatment

I finished my treatment in July 2012. I had 2 lumpectomies, nodes removed, chemo and rad. Shortly after my treatment ended, my arms started itching. I have been living with this problem since then (and a plethora of other issues). I have been to 3 dermatologists, and to my PCP numerous times. We have tried every ointment/cream on the market and numerous antihistamines. I have had biopsies done of the arm and very extensive blood work to get to the bottom of the problem with no answers. Both arms itch intensely and I wake up with bloody sheets from scratching in my sleep. The only relief I get is from either ice or biofreeze. Finally, this past month, my doctor decided to try something different and put me on the lowest dose of zoloft even though I am not depressed. Guess what - it worked! No more itching! This is the first time in 4 years that my arms don't itch! I went in for a follow up and asked why that would work when nothing else seems to be working and she told me that her educated guess would be that I have nerve damage from the bc treatments. Has anyone else heard of this or experienced this besides me?