@anniebrook Erosive osteoarthritis is a subset that principally affects hands and fingers. It may be associated with general osteoarthritis, or occur by itself.

I have found that topical NSAID gel or cream (Voltaren or Diclofenac, for example) is helpful in easing pain without taking the meds internally over a long period of time. Other soothing treatments can include heat or ice - I like a paraffin hand bath when I ache. Steroid injections also work, but if you choose to have one, it may delay surgery because the presence of steroids inhibits healing, so there is a waiting period.

As to your question about who to consult, the Rheumatologist can evaluate your condition, but the hand surgeon (a specialty certification that can either be sought by a plastic surgeon or an ortho surgeon) can operate on it if warranted - you may wish to see each of them.

You do need to act sooner rather than later, though. The swelling on the back of the wrist may well be related to your erosive osteoarthritis - a condition my best friend and I both have. When my wrist became painful & swollen at age 50, my very wise mother sent me posthaste to the hand surgeon, who monitored if for a time, then performed a carpectomy, removing the worst eroded bones, and scraping others. Now, nearly 20 years later, the wrist is shorter than the other but pain free & functional. I have likewise had successful CMC repairs on both thumbs. My friend was afraid to have surgery, and put up with the condition, using splints and Kinesio tape for 10 years. By the time she sought help, wrist fusion was her only choice.

Good luck seeking treatment, and if you choose surgery, make sure to see a good hand therapist after to regain full use.
Sue