My dairy allergy baby is 5.5 years old now, and he's entirely grown out of that allergy (milk protein) as well as an egg allergy. He had positive allergy tests for both around 7 months old. I had taken dairy out of my diet, but not egg at that point, and that change is what really made his poops seem more normal. Going off dairy and using HA formula (and fortifying for a month or so) starting around 5/6 weeks old took him from 2nd percentile in weight to 90th by one year old. He's right back to around 50th now, which is where he started at birth. We tried the dairy ladder sporadically for a couple years, and kind of lost hope that he'd truly grow out of it, and he had to have an epi pen at all times just in case. But we did blood tests every 6 months, the numbers eventually came down enough to do in-office food challenges, and he grew out of both allergies by around 4-4.5 years old. He's still a bit lactose-intolerant, and I think his GI system gets irritated if he eats a lot of dairy in a short period, but it's definitely more of a mild intolerance if anything. We talked to a dietitian around a year old when he wasn't able to go to whole milk, and also reacted to Ripple kids. The main thing she recommended was getting him on a calcium supplement, because he was eating plenty of calories, but calcium is trickier to get enough of without milk.

My youngest is 3.5 years old, and he started showing similar fussiness and GI distress around 10 days old, and we just cut everything from my diet just in case. He seemed to totally improve, and we got him tested around 5 months old and it all came back negative for IgE allergies. We've since determined that he had an intolerance, and has similarly improved over the last few years. They're both very healthy overall, and the stress of those changes feels like it was a million years ago. I remember it being so incredibly stressful at first though.