guupster, every summer (4 seasons in Conn. too, although this year with all the cool wet weather, spring and summer seem to be merging into one) our cat KC gets a swollen bottom lip. It usually lasts about a week, and appears 2 or 3 times a year. At first we thought, because he is an indoor/outdoor cat, he'd gotten stung by a bee. Then we thought he'd gotten the worst end of a catfight, although there were no marks on his face, and he's a lover not a fighter ('nother words, a chicken.) Finally we took him to the vet, after it came back the second summer. The vet decided that he must be getting into something he's allergic to, that only blooms or whatever in the summer. We've never given him anything since it doesn't seem to itch, and the swelling does go away. So maybe Daphne is allergic to something that only appears in the spring and fall--some sort of pollen maybe. Though why it would just affect her back end, I don't know, unless she's sitting in it!! Glad the prednisone helps, though.