Of course the doctor says nothing about finding out what is causing the ear infections, like food allergies. I would remove all dairy, casein products for two weeks (do not replace with soy please). Use Almond or Rice milk in replacements and there are lots of choices. This is a very common cause for ear infections.
Next, if that isn't making a difference, remove eggs, then gluten, then etc. until you find the culprit or have a IgG blood test that will spell out the what is causing the inflammation and then you can remove those.
My now almost 14 year old daughter was extremely sick, all of the time. At 18 months the pediatrician finally did the skin prick test (stupid, painful, does not catch all of the causes) and found egg, soy, corn. Removed those and she still had problems (severe asthma, multiple ear infections - resulting in two sets of tubes - eczema, behavior problems) until age 10 we did the blood test. Found TWENTY ONE food allergies. We went cold turkey that day and removed all of them. She did not have anymore asthma, allergy reactions, colds, eczema, behavior, you name it, problems UNLESS she ate a food that was on that list. Saved a whole lot in doctor visits and more importantly, prescriptions. She was on four daily prescriptions for asthma. Quite the money maker for someone. Singular was one of them and she does continue to take it. We will stop it when she stops sneaking foods to see if they are still a problem. That is another story! lol