Does anyone have reoccuring hives?

One of my close girlfriends had a bad case of hives last summer (had to be on antibiotics, steroids, and I forgot what else). She was under a lot of stress finshing up her law degree and studying for the bar exam.

Now, a year later, she's passed the bar, has a job, and consequently, has less stress in her life (or, at least a different type!)... and her hives have returned! She is extremely frustrated, and is wondering if anyone else has experienced this? Also, she's wondering if the hives were never really caused by "excess stress" in the first place?

thanks!