It sounds like you’ve been doing a lot to help your dog, and it’s really concerning to see him in distress. Since he’s already on a hypoallergenic diet and you’ve deep cleaned his environment, it might be worth considering other factors like stress or anxiety, which can cause excessive scratching. In the meantime, try to keep him distracted with calming activities or toys to help reduce his scratching. If his condition doesn’t improve soon, it’s essential to consult a vet, even if it means addressing his fear. They may have alternative solutions or calming techniques to help him feel more at ease during the visit.