I have had hives breaking out on and off around my body. Can’t figure out the cause. No change in diet, detergents, etc... I was on Macrobid for 10 days for a UTI. I had no reaction on the medication whatsoever while tAking it. After some research it sounds like I could develop hives after I finished the meds. Is this true? How can this be soundly diagnosed? Should I have my doctor do a blood test for kidney/liver/thyroid/ etc issues? If it is a lasting reaction to the Macrobid, could I still have an anaphylactic reaction given the amount of time? I don’t seem to have any swelling and the hives have been on and off for 5 days now. I finished the Macrobid exactly 7 days ago.