I never took my kids to the hospital for croup except for DD1 once because she was really bad - so long as they were comfortable there was no need for it. I just always made sure that I had enough redipred/predmix but if I got caught out I just made do till I could get some, so don't beat yourself up or think you are bad. Its not impossible that he could have gotten it from daycare, but because he's already prone to getting croup anyway, it's probably just coincidence that he's gotten it now after being at daycare. It was more likely that he's picked up a minor sniffle/cold at daycare and that's turned into croup. ANd don't think that climate can affect it - I live in a very dry area and my kids still got it.