My Lab Jingles (RB) broke out in big lumps one night, right before our eyes; red and very itchy. The vet said that dogs do get hives and it's very hard to determine the cause. She was treated with Benadryl and it cleared up fine. We never did find the cause; the vet said it could have any one of a hundred things that she had a sudden reaction to. Saying prayers for sweet Malone!!