Hello! The thing is this: My son has an ordinary mixture. Since 6 mont…

Hello! The thing is this: My son has an ordinary mixture. Since 6 months old, after introducing complementary foods, he has a reaction to dairy products in the form of atomic dermatitis. It's very pronounced if he drinks milk or eats cottage cheese. There's a reaction to cheese, butter and everything else, but it's weak. The pediatrician said to try cooking porridge on milk, I cooked it and there was no reaction. When asked by the pediatrician "so what could be the allergy", she replied "it's hard to say, but you can give him boiled milk". Do you have any ideas about what might be the reaction?