I post this on behalf of a friend.

She has a male flatcoat of approx 14mths and he has periodic bouts of itching under his chin, which leaves him sore and he scratches out his coat.
My friend has worked out that it usually happens just after he has had his Program treatment.
It may be just a coincidence, but she wonders if anyone else's dogs have had a reaction after using Program. 
I've not heard of anything, but maybe someone else has?