Hi,
How are you? Do you still have the symptoms you mentioned? Indeed, nickel allergy is one of the most common trigger for an allergic reaction. Like any other allergic reaction, it important to remove the trigger and to discontinue using the jewelry. Antihistamine medicine may help with the swelling and itching. However, if pain, swelling, redness and discharge is coming out of it, infection is more likely. Antibiotic management may be indicated. It is best that you have this checked by your doctor for proper evaluation. Take care and do keep us posted.
My opinion is that you are allergic to the nickel in the metals that are not gold. So, you can't wear those types of earrings. There is no treatment for this allergy unless they have a allergist who can give you shots to desensitize you. It doesn't sound like this is an option for anyway. After you got the allergy to the metal, then you may have infected it by scratching it. You may need to get to a doctor to see if it is infected too. If you cannot, you can try an antibiotic topical and see if that helps.
mkh9