Hi.. As per your complain hives with severe itching seems to be most probably due to allergic reaction that can be due to a number of causes like any food or medication, leather, latex, poison ivy etc.. I would suggest you to consult an Allergist and get evaluated and a thorough clinical evaluation and investigations like allergic tests like Patch test, RAST test, food challenge test etc can help in diagnosis and treatment can be done accordingly.. The allergist can advise to oral anti allergics as well as injectable steroids for relief.. As of now you can take anti-allergics like Levocetrizine, Allegra to control the itching and swelling.. Do cool compresses.. Application of calamine lotion can help in soothing the skin.. You can also be instilled an Immunotherapy that will help in reducing the severity and frequency of allergic attack.. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Honey Arora, Dentist