You should do a search on what Aimee recommended-usually ear infections are caused by something (usually allergies-but sometimes just from getting the ears wet). Also, I changed Baylee's food and within about 2-3 weeks her ears were clear and have been since. I didn't use Otomax in Bay's ears, we used Panalog ointment (it has another name now-Animax I think it is called). I would just massage it into her ear and the infection would go away. But, right after I stopped it about 1 week later she'd start itching again. That's when I finally decided I had enough and changed her food.
Good Luck,
Jaimie