My symptoms and dx sound similar, only difference is timeframe. I'm just shy of having my hives for 12 months. They are very severe, like you. Swollen from head to toe, ears, palms, and sometimes big giant lips and eye's swelled shut. It has been the worst year of my life. My Dr has basically said my immune system is 'confused' and thinks it is fighting a disease that isn't there.
I am currently on Zyrtec for day, and Singulair, Doexpin, Atarax at night. Prednisone thrown in on occasion when I swell too much or think I'm going to loose my mind! The only time the hives are gone is when I'm on a high dose of the Predn. One thing that *DID* control it is Sandimmune, many doctors are hesitant to use it, since it is an immunosuppresant. It is commonly used for chemotherapy and with organ transplants, I was only allowed to be on it for three months. I am hoping to go back on soon, since it's the most relief I've had this year. My Dr. said it often put's autoimmune hives into remission. Not so in my case, but she wasn't surprised since she said I have one of the worst cases she's seen in her lenghtly career.
It might be worth checking next time you have a flare up.