By the looks of your picture, I must assume that it is a puppy. It is definitely one of the Spitz breeds. All Spitz dogs, large and small have specific characteristics in common. The have long thick coats, pointed ears and a thick tail that is carried over the dog's back.
Most Spitz dogs are named either for their size or the location where they were first developed. Since there are several dog breeds that are all white, I can't know for sure what breed it is. However, my guess is that the dog must belong to one of the following breeds:
Pomeranian American Eskimo Dog German Spitz Danish Spitz Japanese Spitz Volpino Italiano
Some of the large breed dogs that belong to the Spitz family include:
Keeshond Alaskan Malamute Siberian Husky Chow Chow Akita Inu If anyone has other ideas, please add your comments below.
Whatever the dog is, he or she is very cute and I'll bet has a personality bigger than she is.