I Have Had Itching And Rashes On My Legs, Elbows,

I have had itching and rashes on my legs, elbows, and sides of my stomach. I also have kidney damage and anemia. I take Benadryl one to two hours before bed, and use plenty of extra strength cortisone cream a half hour before bed, however the itching is still keeping me awake. What can I do to make the itching go away enough to sleep?