Severe itchy rash to torso and upper extremities

I am a wound care nurse in a long term care facility.  Along with wound care, I also deal with "skin issues" for our residents. I am currently looking for help with a rash that has a severe itch and red "bumps" on the torso and upper extremities.  This is a rash that is spreading and scabies has been ruled out since they were all treated with medication for scabies.  Everyone that is able to describe the "itch" describe it as horrible.  Topical steroids as well as oral steroids, and an antibiotic have all been tried.  During the treatment the rash and itch gets better, but once all is completed, we once again have a severe itch and rash all over again.  Some have the red bumps, others have a red raised scaly type rash, some have small scabs.  The rash is only on torso and upper extremities.  Please help does anyone know what this could be?