I have never heard of this either, and I've also not heard of the drug.
However, her progesterone will decrease significantly after birth, and
maybe, just maybe this will result in less severe problems.  If it is
autoimmune, why not use steroids, such as prednisone, which is certainly
compatible with breastfeeding and with pregnancy?  At the very least,
she could decrease the dose of antihistamines, which, in any case do not
appear to be working.  I am not sure that antihistamines decrease milk
supply, but we've been that route on Lactnet before.  Still, prednisone
might be the way to go.

Jack Newman, MD, FRCPC