What Causes Rash And Itching All Over The Body?

hi i was diagnosed with scabies but the doctor never did a skin test he just looked at my rash for 5 seconds then automatically assumed it was scabies. im itching everywere my neck back legs hands feet chest breasts, i was prescribed Permethrin cream 5% and i used the entire tube over the course of 4 days, kept it on for 10 hours then washed it off in a hot shower, i was my linens and bed stuff and clothes everyday in hot water i even went to the extreme of bathing in 1 cup of bleach in hot water and the next day a hot bath with 2lbs of sea salt and to no avail im still itching like crazy is there a chance of mis diagnosis or if it is scabies how do i get rid of them once and for all im going crazy!!