pattyClink - While ventilation is important, another factor that's recently been recognised is that humidity is death to the little scamps. Don't let your home get too dried out. (I don't know how to measure humidity, unfortunately, but reckon that giving the washing a final dry on racks and radiators probably helps.)
bonzo3legs - Sympathies for the greyhound. I used to have a dog that had big trouble with eczema and it turned out to be mainly triggered by milk. My current adored-one gets diarrhoea from milk.