Good news, my son may be growing out of his milk allergy at 7 1/2 yrs
old. He's also allergic to eggs, nuts, legumes, and barley. since
birth he reacted to milk even touching his skin (and also had eczema,
asthma and lots of colic before the milk allergy discovery). We tried
him on  milk for a few days every 2 years. Last time, 2 years ago,
he'd get asthma during the milk tests- coughing at night, and
wheezing during any activity. This time he's so far ok with drinking
cow's milk, but cheese seems to be giving him loose bowels. I'm
keeping him off cheese for a week to see if the bowel problem may be
some passing sickness instead.
Maybe we'll stay off cheese a bit, but not have to be as vigilant
about the dairy equipment labels (boy, that reminds me- as a toddler,
if he got the milk contamination, he'd run around the kitchen table
30 times, non-stop).