Hi my son had hives on Wednesday I took him to his pediatrician and he was unable to pinpoint the cause. He prescribed prednisone and zyrtec. Hives went away. However, they came back again today- brought him back to the pediatrician and the pediatrician advised to keep him on the meds for a few more days stating that these hives could come and go for a week. He just had a bad outbreak of hives an hour ago, on his face, ears, and arms. Seems to be on only areas that weren't covered. No hives on stomach, back, chest or feet. He just took a cool shower and they are pratically gone. any idea what could be causing this? could this be viral?