Rheumatoid Arthritis Support Group
Rheumatoid arthritis is a chronic, inflammatory, multisystem, autoimmune disorder. It is a disabling and painful condition which can lead to substantial loss of mobility due to pain and joint destruction. The disease is also systemic in that it often also affects many extra-articular tissues throughout the body including the skin, blood vessels, heart, lungs, and...
as you know, the inflammation in the joint affects the surrounding area of it too......like muscles, tendons, ligaments, bone.
so i think the swelling between your index and thumb might be with this inflammation. if you can stop working (if you have any chance), rest for a couple of days applying heat and cold. hope that helps.
why dont you give a call to your doc and see what they say?
hope you feel better.