Since this topic came up recently with a friend of mine, I thought I would give my experience here as well.
When my daughter, Ivy, was between the ages of one and two years old, she had chronic ear infections. Sometimes I would be oblivious of the fact, since she has a high pain tolerance, and the doc would diagnose her when we were at the office for another reason.
Mind you, this was occurring before I became aware of how many allergies I actually had.
Anyhow, they persisted even through FIVE rounds of antibiotics, starting with the usual Amoxicyllin and working up to the Augmentin. Once we got to the Augmentin(twice), the family doc finally gave up and referred us to an ENT.
The ENT had Ivy's hearing tested, and she was indeed having some difficulty hearing everything. Not enough to be overly worried about, but enough to keep a close eye on.
We then had the ENT actually look in Ivy's ears, and sure enough he could tell she had obviously been going through a LOT of trauma due to the infections. He recommended putting tubes in her ears ASAP but could tell that I wasn't too hip on that idea if there was another option. I asked him about food allergies and his opinion on them in relation to chronic, persistent ear infections. He responded that he had actually seen a case in which the child was allergic to milk and had chronic ear infections and when the milk was taken out of his diet the infections went away. He was a bit skeptical at that point, as the ear infections came back a few months later, but his skepticism vanished when the mother figured out that the child was getting cheese at daycare(the daycare provider had figured that "a little wouldn't hurt"). Once the dairy(cheese) was eliminated from the diet, the chronic ear infections again went away.
The ENT suggested I go off of dairy myself(I was still nursing her at that time) and take Ivy off of all dairy. We did this, and at the next month's checkup, her ears were healed and her hearing was back to normal! The ENT and I were both thrilled with these results, and we obviously didn't get the tubes put in. Ivy and I both continued to be dairy-free until around June of the following year(about 6-7 months).
Once Ivy's ears were healed, I did use xylitol for Ivy as was used in this study. I used the powdered form purchased from the health food store, and figured out the proper dosage. I fed it to her from a spoon. Even now I give her gum with xylitol if she is fighting a cold(as that is what usually precedes the infections). I also gave her Sambucol to help boost her immune system if she seemed to be fighting something. If I was fortunate to find it, I gave her the Sambucol with Echinacea for 3 weeks, then the regular for a week, then rotated back to the Sambucol with Echinacea. You don't want to take Echinacea continually, because it loses its immune boosting power if you do.
Since that year(2007), Ivy has only had one ear infection(a year ago last April). She does get dairy now, but I cut way back if she is fighting a cold or other illness. I don't push the milk; she gets maybe a cup a day, if that. We do have kefir, yogurt and cheese, but not everyday.
I had suspected milk allergy in my second son, Hunter, as he also had a lot of ear infections as a toddler. I didn't have the knowledge of allergies behind me, though, to figure it out and help him better. I wish I had, and had been able to keep him from going through those painful times!
At the next visit to our family doctor, I reported our experience with the ENT and the success of avoiding the tubes simply through avoiding dairy in our diets. She replied, saying most people would rather just get the tubes than have to worry about what their kids are eating all the time. Wow. People would rather put their kids through (unneccessary, in the case of allergies) minor surgery(that carries risks) and antibiotics that further compromise the immune system just for their own convenience? Talk about treating the symptoms of the illness rather than dealing with the underlying problem! I am betting that those who ignore(or are ignorant of) the allergies will have it creep up later in life. An ignored problem doesn't always go away; it often has a habit of showing up somewhere later on...often more serious and harder to deal with.
As a sidenote--I think there is a correlation to my kids' ear infections and to the introduction of milk products at 1yo. I was still nursing when my kids were that age, so I didn't give them plain milk, but they were getting other milk products at that time, and that's when the ear infection problems started. So, that said, if you have allergy issues in your family, I'd recommend waiting way past the 1 year mark to introduce dairy products, as milk is the most common allergen in babies and children.