Skin itch after Rituxan infusions

I need some help stopping this itch! I started Rituxan infusions on June 20th and since I have had an odd skin itch that is not going away and keeps getting worse even after infusions are long done. There is no rash, the only marks on my skin are due to my scratching. I have tried doubling my prednisone for a few days, I have been on Claritin, Benadryl and Zantac. I have pharmacists, the best allergist and my Rehumy totally stumped. I don’t know what else to do. I am going crazy and I’m suppose to go back to work on Monday but I can’t go to work looking like I have flease all day. Evening are worse I actually use a brush to scratch so that I do not cause as much damage and can get some relief cause the itch is unbearable! Showers do help so I take about 5 a day especially at night so I can get some sleep. Any suggestions to make this stop I would love it! Thank you!