Our experience was somewhat similar. We discovered that our second child (our
first has no food allergies and is now 13) has an anaphylactic allergy to milk
and milk proteins, like casein. He had plenty of symptoms, which we attributed
to other things -- like ear infections, reflux, clear runny noses, lots of
gas, etc. We thought he was lactose intolerant. I breastfed through the first
6 months and then he went on to soy formula. We made all his food at home.
When he was about 10 months old, we began introducing cheese, yogurt and milk.
With each incident, he had a different reaction, starting with a mild rash
around his lips from the yogurt to a clear runny nose from the cheese to hives
all over from the milk.
Our doc told us to avoid milk for a month and then try again. Well, she didn't
tell us about casein or other "hidden" milk ingredients in products. No one
suggested we stay away from deli meat at the regular grocery store because of
possible contamination from cheese (on their gloved hands) or because some
meats have milk fillers. No one told us that "non-dairy" didn't mean
absolutely no milk.
So we made a few mistakes while learning.
The best advice I can give you to help you start (if you find you must keep
milk out of your daughter's diet): contact the Food Allergy Network
<A HREF="http://www.foodallergy.org/index.html">Welcome to The Food Allergy
Network</A> and keep communicating with groups like this one.
Both have been real life- and sanity-savers for me and mine!
Good luck.

Rose