It can sometimes help if the mother avoid dairy when breastfeeding.

AFAIK breastfeeding reduced the risk of allergies in general, but
doesn't remove it.  Also, weaning early (or never breastfeeding) can
make life extremely difficult if the child is allergic/intolerant of
milk.

Problem is, the medical profession is fighting an uphill battle with
some mothers just to get them to breastfeed, a suspect I understand the
white lie.

Megan