I had the sme problem!
Im new, and I joined this board tonight to find out about hives and swelling. My little 1 year old flashy fawn girl got that terrible swelling about 4 months ago. She had gotten hives several times before--small bumps that looked like mosquito bites but i knew boxers were sometimes prone to this so i didnt worry when she got them, plus the breeder told me her mother got them occasionally and not to worry. On to the swelling.
Well, one late night her eye lid swelled up. First it was the size of a grape, then a golf ball then a tennis ball. Then the other eye started swelling, along with her ears, top of her head and then in the morning her jowls. It was terribly heart wrenching. I was hysterical. I had given her benadryl when the first eye started, i just thought she had been bit. The swelling happened fairly fast and in the middle of the night her eyes were swollen shut. By morning i couldnt even look at her. I was a wreck and had to go to work. My fiance took her to the vet and they assumed she ate moldy walnuts. ??? They gave her a shot of prednisone and sent him home with pred. tablets and advised to keep her on benadryl until swelling was all gone. She recovered fine and we kept her from eating any fallen walnuts. Then again one night about 1 month ago, her jowl swelled up suddenly--she had been no where near walnuts! I gave her the same meds. the vet gave us from before and she was fine a little later. That's when i knew it wasnt bad walnuts, it was simply related to the whole allergic reaction/hive situation that she is prone to. So now i keep pred and benedryl on hand wherever we go--just in case. Im hoping this is the type of reaction that gets less and less severe with age. Her 2nd was significantly less severe than the 1st. So i hope this helps you out a little. Im glad my baby isnt the only one who has experienced this.