Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain it seems that your sister is suffering from
allergic reaction as the symptoms of rashes, itching and
swollen tongue seems to be due to allergic reaction..
It can be due to causes like any food or medication,skin cosmetics, poison ivy, leather and latex, bug bite etc..
I would suggest you to consult an Allergist and get 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 avid exposure to it to prevent allergy attack..
He can be advised to take anti allergics like
benadryl along with steroid nasal sprays to relieve the symptoms..
He can also be instilled an
Immunotherapy that will help in reducing the severity and frequency of allergic attack..
Once the allergen is ruled out avoiding exposure to it can prevent the allergy symptoms..
Hope this information helps..
Regards..