Hi.. Thanks for the query.. Allergic reaction causing itching and hives on the body can be due to a number of causes.. Common ones are allergy to any food or medicine [if you take], any skin cosmetics or soap and detergents, leather, latex, bug bites or bed bugs etc. If after steroid shot and oral medication also you are still having the symptoms you should consult an Emergency room and get allergy tests like Patch test, RAST test, food challenge test etc can help in diagnosis and treatment can be done accordingly.. The tests will help in ruling out the exact cause of the allergen.. Once you know the cause of the allergic reaction you can avoid exposure to it to prevent allergy attack.. 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.. Also discuss about Immunotherapy in which small amounts of allergen is periodically injected in your body and the body gets used to it thereby reducing the allergy symptoms.. Hope this helps.. Regards..