My Husband Has Been Battling What We Have Been Told

my husband has been battling what we have been told is allergies. These are not the typical seasonal allergies that result in sneezing etc. but instead something that seems to be an ongoing skin irritation. He's been on rounds of steroid treatment, Prednisone. When taking the Prednisone the symptom dissipate temporarily. But not long after he stops taking the Prednisone the symptoms return, specifically, lumps and bumps on his skin that ooze. These areas are extremely itchy. We are at our wits end. He's been told he's allergic to clay, chrome, oak and a number of other things, but it doesn't seem he even seems to be in contact with any of the things he's allergic to for the symptoms to appear. It almost seems like its something in his blood stream causing the symptoms to continually return. I've spoke to a few others in the area who are experiencing similar problems. Any ideas?