the dog may be allergic to the frontline. My neighbor's dog's hair fell out and she started scratching uncontrollably when they switched from frontline to frontline plus. Another possibility is all these chemicals the dog has received at once; like the vaccinations, flea repellants and skin meds. Chemicals tend to lower a dog's ability to fight things off themselves. Bathe the dog in a fragrance/soap free shampoo...something very basic, but be careful not to overbathe. Earthbath is a good one to use for things like this. Since it is very likely the food is the main source of the problem, switch to a natural diet with no corn/soy/colorings/etc.