Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain itching and rashes on face and even legs  seems to be most probably due to 
allergic reaction and it can be due to causes like allergy to any food or medication while it can also be due to 
Contact Dermatitis caused due to Poison ivy, allergy to skin cosmetics, soaps and detergents, poisonous 
insect bites 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 tests will help in ruling out the exact cause of the allergen and 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..
You can also be instilled an 
Immunotherapy that will help in reducing the severity and frequency of allergic attack..
Hope this information helps..
Thanks and regards..
Dr.Honey Nandwani Arora..