The Asthma & Allergy Advance, Vol. 10, Num. 8, May, 1992, issue
had an article by Kenneth P. Mathews on Chronic Urticaria.  My
allergist gave me a copy of the article when he prescribed
hydroxyzine, which I took for about 6 months.  

I didn't find the article particularly helpful, but my allergist
said it was about all there was in print right then (1993).  He
also said that since hives aren't life-threatening, they aren't
likely to be a hot research subject any time real soon.

I stopped taking hydroxyzine when I found that the side effect
of feeling stupid was more disturbing than the itchiness of the
hives.  Soon after that, the hives finally went away for good.

Good luck.
--
Kate Schaefer