
I have used Frontline spray for several years (five or so) every three months on my lot as a preventativbe. I use the spray as it is active for up to three months as opposed to two with the spot on, and works out cheaper!
I started this when my oldest bitch had a summer of looking like a moth eaten patchwork quilt due to flea allergy dermatitis, even though the Vet and I never found any fleas on her!
I have had no problems with Wet Excema since I started using it!
I also always used a household spray twice a year, one that has a growth regulater, that stops flea eggs hatching. I must admit now that the last year I have not used the Household spray, as I have had no flea problem all these years since using a product on the dogs as a regular preventative!
Froontline is only effective on ticks for 1 month, in case ticks are a problem in your area. In 13 years of Dog Ownership in Bristol I only ever had one tick, on my very first dog 12 years ago. They can be a problem in some areas!