By scratching his ear with his foot he could be transferring a yeast infection from his ear to his foot. Then he rubs his face with his foot and transfers it elsewhere, maybe, could be, my VEt said when I had that problem.
Personally I did not hesitate to give the two week dose of antibiotic, My dog had not yet transferred an infection from his ears to anywhere but I wanted to forestall that possibility. Actually it was a 3 week dose because the first antibiotic did not work as well as hoped and we had to use a second one. They were ear drops, not oral.
I realize that is probably exactly why some folks are reluctant to use anitbiotic at all, because some strains of some things have become resistant. Plus the chance of tummy upset and other side effects. We did not have that and it would have been temporary anyway. It's long term antibiotic use that is frightening to me, not a couple of weeks.
With my dog it was just a "thing" he developed. He stayed on his same treats, same food, same dish and once it cleared up it didn't come back.
For you to consider. When it gets to their eyes it really scares me.