Hi..
Thanks for the query..
If the symptoms of itching has not got any better then it can be probably due to some other allergens...
Blistering and swollen arms and ankles can be due to
hives caused due to some unknown allergen..
The other causes can be foods, bug bites, mites, poison ivy, soap and detergent etc..
Consult an Emergency room and get evaluated..
Anti allergics like Levocetrizine or
Benadryl can help in reducing itching and rashes..
Apply
Caladryl lotion to soothe the skin..
Do cool compresses over the rashes..
You can also be advised
Steroid shot to relieve the symptoms faster..
Also get an
allergy test done to confirm the exact cause and try to avoid exposure to the allergen..
Hope this helps..
Regards..