I wanted to say something about the apparent confusion it seems about
whether the mother can "cause" allergies through eating something she is
allergic to while pregnant.  I have 2 allergic babies and I too have food
allergies, some are the same, some are different.  My opinion is that the
predisposition to developing allergies is genetic, so being atopic, or
reactive, may be inherited.  However it is in utero and during
breastfeeding that the tendency will bloom into fullblown allergy (with
the body creating IgE specific to the food in question and the reaction
becoming more and more developed.)  My take on milk is that the baby can
be exposed in utero but I don't think it matters that the mom is allergic
to it or not (ie. a non milk allergic mom could drink dairy and expose
baby who could become 'sensitized' to milk through this exposure, or vice
versa).
        I tolerated dairy when pregnant (and really wanted it) and it did
not ever occur to me I was sensitizing the baby.  I also ate many nuts and
a lot of grains being on a gestational diabetes diet.  (Baby turned out to
be very allergic to all of these and many more things that I never ate,
BUT I do not believe the baby would NOT have been if I had not eaten these
things.)  I think sooner or later the exposure would have taken place and
the reactivity that was genetically encoded would have gone into action.

        With my 2nd child, I did avoid dairy more and also eggs and nuts
to give her more time to develop without becoming sensitized.  She still
showed dairy reaction if I consumed anything like one piece of cheese as
early as 2 months (eczema behind ears, itchiness,
fussiness).  Overall though she seems much less allergic but again, I do
not attribute it to my diet during pregnancy.  I still think she may be
completely predisposed to all of my son's allergies and I am dreading the
possibility that she may develop these.
        I still breastfeed her almost exclusively  (I still avoid
dairy, eggs, nuts but not excessively, I just don't sit down with a bag of
peanuts or a plate of scrambled eggs), and I barely feed her table food
(at 8+ months).  She eats a little organic fruit-meat puree or rice-plum
mix (note: none of the allergens of the brother although I know hers might
turn out to be the opposite of his, I am just too spooked to plunk her
down with a box of Cheerios, plus of course, her brother is going to
want whatever she's got). I don't plan on feeding her what
most people feed a 6 month old til after she is 1 and no nuts/eggs til
after 2.  I can't decide about the wheat and grains (still dealing with
possible celiac condition in the first, at present undiagnosable because
he has been gluten free for so long; this too is hereditary).

Anyway, I hope you get the idea from this... it sounds like you are really
worried that you somehow gave your child these allergies. I know I had
food allergies (and my husband has skin-air allergies) which made us
extra- likely to have allergic children.  I am going to tell my son and
daughter when they have children that they should be very careful... The
most important thing they can do is recognize allergy when they see it: an
itchy fussy, gassy baby, and NOT feed the baby food til his/her digestive
tract is mature enough to process these troublesome proteins.   Breastfeeding
 is still the single most important deterrent for avoiding the worst
consequences of infant allergy in my view.

Susan, mother of Nicky and Emma.