Suggest Treatment For Hives In A Child

My 6 year old has been breaking out with hives for a week now. I have taken her to the doctors twice. On the second visit they ran a rapid strep and came back positive. She has been on antibiotic for 3 days now. Should she still be breaking out in hives? They have seem to be worse now than on the first day. How long will it take for the hives to completely go away?