>.  If I touch the back of his hand with a drop of
>milk, no real reaction, but if someone kisses him in the same place after
>eating, whoooa, watch out!
>

This could also just be due to a person's mouth breaking down the
carbohydrates to sugars. Many people get contact reactions from sugar
on their skin. On safety sheets sugar is listed as an skin irritant.
Have you ever tried making a sugar syrup and placing it on his skin?
Maybe you may have seen irritation around his mouth after a sweet
snack or juice, too. This could then just be due to the sugar.  Just
a thought. My son did react to milk products touching his skin when
he was < 5 yrs old.

My pediatrician pushed the idea of goats milk for my son, I never
tried it. I supplemented Calcium with some vitamins and fortified OJ
instead.