What Causes Chronic Itching All Over The Body After An Open Heart Surgery?

Hii, my name is Michael. I had open heart surgery on 12.24.16,, ( I was under anethesia for 5 1/2 hours ) & not after that I began to start itching. It wasn t that bad while still in the hospital, but it did get progressively worse to the point of scrathing INSANELY all the time ! I went to the ER, & was told I had scabies & was prescribed Permethrin 5%. It did nothing. The iyching began to get worse ! I made a trip back to the ER, & was told the was no way I had scabies, & prescribed Urea lotion 10%, after my shower, then wait 5 or 10 minutes & put on Clobetasol Propionate 0.05%, it didn;t help at all. I made an appt. with another Doctor, & She prescribed Clobetasol Propionate, & Hydroxyzine& agree the the second DR. that it wasn t scabies. The itching persisted, & by now I thought I was gointg to lose my mind !! I did got to a fourth Dr. & He concured it was not scabies, & gave me a prescription for Triamcinolone 0.1 % & Clobetasol & Triamcinolone Acetonide 0.01 %. . . . to date nothing has helped & my question to You is could all of this itching be from the anesthesia ? All four of the Dr.s said I don t know what this is, & I m still itching, & going out of my mind ! thank You So Much Michael L.