DS (9) has not had chickenpox before.
He's had a hacking cough and temp for two days, and he's been out of sorts. I just put it down to a normal winter virus thing. But this evening I have noticed he's got a faint (blanching) spotty rash on his back. Just been up to check on him and he's sweating buckets but with no temperature 
My suspicion is chickenpox. If your DC have had it, were these similar to the initial symptoms?