I'm 74 and still am unable to tolerate any dairy - so am 100% dairy free since the 1970's. It started the 2nd week after birth  with projectile vomiting + diarrhea. As an infant I was switched to raw goats milk, which I tolerated somewhat better, with rice gruel. Then, in my late 30's when I was having violent episodes, in and around pregnancies and some concern I would loose a particular baby, that it was finally addressed again. It was then that I saw GI specialists, who all proved to be useless. Then, finally a friend recommended a old-time allergist who was interested in food allergies. He did skin/blood testing + an extensive food diary [that finally was the key]. I found that dairy was not the only culprit, but certainly to main one! It has been very difficult to diagnose me because my allergy symptoms are not always immediate. FPIES fits me to a tee -- except for the fact that everything I see says that babies and children out grow it. If in truth, that is what I have..... 'taint always so! If I get a hold of even minute amounts of dairy my body goes crazy and I go "toxic" just like when I was a baby. It can last anywhere from 3-7 days or longer.