[Anonymous]

“If this season is typical, most of this will be over by summer”.

Or, not. If the symptoms have been going on for 4 seasons/1 year without significant periods of relief, and the dog is still uncomfortable despite diet changes and visits to the regular vet.
It is time to see a specialist, veterinary dermatologist (imo), let him advise you as to what testing is indicated after examining your dog and learning it’s history.