Will Falconer, DVM Moderator
Nyguard is relatively very safe, yes. I'm not sure how effective it would be on carpets. You'll see on this page that I'm recommending it for bare floors.
DE is great in the garden. It's a mess in the house, it dries out the dog's coat if it's used topically, and I mean, would you like tiny little sharp crustacean skeletons on your skin? I much prefer borates, specifically for carpets, inside couch crevices, etc.
I recommend professional help from a vet homeopath if skin disease is already present. Nothing topical comes close to the healing homeopathy can effect. Told how to find one in the free Apoquel Alternatives Report.
Smart vet, but "infection" is the wrong word. In general, "anti-" anything is a bad idea.
"A stimulated immune system is a balanced immune system." Got that gem from a scientist years ago when I had the same concerns. I'd give any auto immune patient, especially in a crisis, high levels of transfer factor to try to re-establish normal balanced function.