What Causes Redness And Itching In Fingers?

I have occasional sudden-onset intense redness and itching in my fingers, followed by hard nodules, and sometimes by instantaneous hardening and thickening of my finger joints. I don t know what this is. It happens every so often. I ve started using tea tree oil on the newly inflamed nodules, which seems to shrink and destroy them over a period of three to four weeks. Any ideas of what this condition is called? All my doctors says is that it is arthritis, but undefined.