I think the steam/night air thing depends on the child & where you live.

Steam is what works for us. Night air is what sets it off... I think if the air is humid it works, but if its cold it doesn't. If my kids are croupy, they can't be outside past 4pm coz it gets worse.

DD3 recently had a bout & when she woke through the night I steamed up the bathroom til she crashed out & she slept the rest of the night. I think it must be differen't for different kids, coz my kids ONLY get croup at night. I assume there's a reason for that?