It seems like there are many more children with food allergies these days. I've read a bit about this, and although there are a lot of theories out there about why, I'm pretty sure that the medical community doesn't really know why.
When my third child was born, she was diagnosed with an elevated white blood cell count. She was also jaundiced. After a bit of testing, (including a spinal tap that I watched them do on her in the NICU - ugh, that was painful...) A round of antibiotics was prescribed. As a newborn, she was an inpatient during the course of medicine, which meant for a week. We had been through something similar with one of the other kids, so we tried to take it in stride and just wait for her release from baby jail.
While she was there, I nursed her and pumped to develop and keep up my milk supply. I had experience with this, too, so it was difficult but not a big problem. We just wanted her home.