So far, all of the so-called "non-dairy" cheeses that we've found contain
casein. Some people who are allergic to dairy proteins can tolerate casein.
There are even separate skin tests for casein (blood tests too, if I recall
correctly).

My son and I have reconciled ourselves to eating cheese-free pizza. We either
make it ourselves (using store-bought or home-made dough) or we go to one of
several pizza places that use dairy-free dough and make a mean, cheese-free
pie.

Mark