[WesleyandMaddie]

Originally Posted by alaskayorkie

You may have already done this, but I'd start with a vet. That's highly unusual for a 2-year-old dog to suddenly start acting aggressively. I would suspect a medical problem. A friend of mine has a Great Dane she raised from a pup. It attacked her one day, and she was ready to put him down. But it turns out he had a tooth infection. They treated that, and he's been lovable ever since.

Definitely start with a vet, then look to a behaviorist if the vet has no answers.

This is great advice.