There's apparently a "family" of Pyoderma. After your post I searched on line and kept finding Pyoderma Vegetan, which sounded pretty much like the rash I had.

Pyoderma Gangrenosum talks about open sores (and showed some really gross photos) and outbreak I had didn't have open sores.

There was another kind of Pyoderma (with another word starting with an H, I think).

Tonight my mother looked it up in a fairly thorough medical dictionary and found just pyoderma and it said something like - a variety of skin conditions.

Thanks again, Wi, for giving the correct spelling to me. I would NEVER have found that on my own!