I Have Red Bumps And Rash On My Chest, Arms,

I have red bumps and rash on my chest, arms, armpits, that are extremely itchy. Continuously without just being a flare-up of some kind. I have been seeing a dermatologist and allergist/immunologist who believe it is eczema and dermatitis. The eczema on my hands and behind my knees, makes sense. But these bumps and rash on my chest, back and arms looks like a huge hive that constantly itches.