I vote for the benedryl and skin so soft. Skin so soft will help keep the fleas away. When we lived in Florida, we would soak my dog in a tub of warm water and skin so soft. We would just sit with him and keep swishing the water over him.
We had another dog later on that was allergic to everything green and growing. But she had to be an outside dog since she could not control her bladder. The Vet advised the lowest dosage available in over the counter benedryl.