Crusty ears

Hi everyone. I have a 7 year-old black and white male indoor cat named Toonces. It seems that every spring/summer, the skin on his ears gets crusty and the fur thins out. Sometimes the sides of his nose (from the tear ducts) become red as well. We asked our vet about this and he said it might be allergies. Has anyone had this happen to their cat, and do you know if there's some kind of cream we can put on his ears? He doesn't seem to be bothered by it, but I don't imagine it's a good thing.