for the last bout of urticaria, my allergist (MD) prescribed a course of steroids, followed by the antihistamine Avarax, a new <span style = 'background-color: #dae8f4'>fast</span>
acting AH that seemed to do the trick.
if you've tried everything and nothing works, you can look into Chinese medicine, herbs or even acupuncture, which my neighbor (had full body hives for weeks) tried. It took one week using herbs and acupunture for hers to completely disappear. Hang in there, it's not forever.