I Have Taken My Son To The ER 3 Days

I have taken my son to the ER 3 days in a row. He is having an allergic reaction to something. He can go 5 hours without eating and it will happen. Everything is being monitored, washed and re washed. Is it possible that a meningitis shot "B" from 8/5 is causing this or internal & external stitches he received on 7/14 could be doing this. His first reaction was on 7/22 when we arrived in Rome. 2nd one yesterday even. Third one this AM and now one after the steroid and antihistamine shots have worn off.