Hi My 2-year-old black labrador had developed an irritation on his face. He scratches to the point that his skin gets dry and has bald patches. We've had him to the vets on numerous occasions. He's on Royal Canin Anallergenic dog food and has been taking Apoquel to ease the itch but as soon as he comes off the medication he's back scratching as bad as ever. The vet has taken samples but they've come back negative. This has now gone on for 5 months. Does anyone have any suggestions?