re: chronic hives -- I learned having had chronic hives for one year, that prednisone is the best antihistamine tho' side effects are awful. It does take time and more time to be rid of and noone really knows the cause I had had hip replacement surgery and I am sure it was the metal in the replacement that caused my hives.By now I guess my body has adjusted. Once in a while I get a small hive.I take Zyrotec 10 mgs per day. My seige was awful with 6 varities of hives! Noone had seen such a bad case! Even on my tongue! And 6 different kinds!!! Good luck! Believe me docs do not know the cause unless it only lasts for 24 hours. Pis another famous cause.