I'm not sure if Fancy had hives or what but I called the vet out and he gave her a shot of antihystamine (sp?) and they went away immediatly. That's been many years ago and I sort of remember that I thought she had gotten into some red/fire ants. It was all over her neck and face. You might check around for ant hills.
Edit: It might have been epanephrin (sp?) that the vet gave her