There are a few things you can do.
A hypoallergenic food can help.
An otic cleanser like Zymox or an ear powder like Thornit (have to special-order from the UK, a poodle rescuer friend says this is the best) are also good things to try.
You also have the physical attributes of the ear to consider. Dogs have a vertical ear canal, unlike humans, so moisture will fall down into the ear canal after swimming or bathing and is difficult to remove. Keep the ear canal well-plucked, use cotton balls in her ear during bathing to keep out water, and consider shaving her ears. If you can’t bear to shave her whole ears, shave about a 1.5 inch wide strip. A friend of mine with a Standard male does this, and while it looks different it does have kind of a cute pig-tailed look– and the lack of hair helps the ear canal dry out and become less hospitable for bacteria.
Good luck!
