My Right Hand Started Itching 2 Days Ago And Is

My right hand started itching 2 days ago and is now swollen, I also have welts that show up on different parts of my body but go away. Now my right hand isn't itchy as badly but still very swollen. My left hand started itchy extremely bad today when I woke up. I have tried using benedryl to relieve the itching but is not helping.