I get that cr*p every time I ask.

The pat answers are either:

1) there's no protein, so it won't trigger allergic
reaction
2) there's not enough lactose to make a difference.

I find neither of these to be entirely true. I have
symptoms when I eat/take anything with lactose and/or
milk proteins in it. So does my son. It's the symptoms
that are the true "test."

I find it appalling that allergy medications are so
often buffered in lactose, and that allergic reactions
and  diarrhea and related GI symptoms are so commonly
listed as side effects. When will they get a clue!?

In your specific case, you might want to consider
Allergra tablets, which are lactose-free.