a dog cannot get poison ivy. While it can carry the oil on its fur and pass it to people, the dog will not experience any symptoms. Benedryl is an option for immediately relief, if the itching is really bad or if they have possibly been exposed to an unfamiliar pollen/mold/dirt but it would seem odd that all the dogs are showing the exact symptoms, at nearly the same time...that would almost certainly eliminate their diets. Winter is really dry and possibly they are just dealing with winter dry skin. I will suggest something that others may disagree with here...I give my dogs a raw egg on their food in the morning. Their coats are always shiny and oily. If you have recently bathed them that may be something else to consider, may be a different shampoo. But that is another issue in itself.