Aren't they just a mild allergic reaction? 
An allergy yes - mild?  In my case no.  Hives or Urticaria, is named after stinging nettles, as they produce the same sort of weals.
There are different types. I suffer from pressure Urticaria, which means if I scratch myself or my clothing is too tight I'll come up in an itchy weal. Of course it a vicious circle the more I scratch the more weals the more I itch....eventually you draw blood.
After getting little help from the medical profession, I eventually worked out it was an allergy to diary product, in particular high fat cheeses.  Over the years its calmed down, but I still can't eat diary products in any great amounts. 
I found the topical steriod cream the doctors gave me  (eumnovate) worked, but came with such dire health warning I tried to avoid them.  Surprisingly I found zinc and castor oil cream mean't for  babbies nappy rash worked just as well and is safe to use over a long period of time.
I seem to have got carried away here and its nothing to do with rabbits!...hope its useful never-the-less.