2yrs old got hives and itch all over his body

Janice

My son is 2yrs old, he got hives and itch all over his body. I went to emergency and doctor said it may go away in 2/3 days since h got a fever 3 days ago. But I really concern about it if this is not caused by the fever. And the doctor said the hives not from the teething as well. Anyone have the same experience? My son doesn’t get any allergies before.