It sounds like you have been through quite a diagnostic odyssey in the last 10 years. I recommend that you revisit a rheumatologist
. The rash that you are describing could in many ways be consistent with primary biliary cirrhosis, as you have probably been told that significant itching is unfortunately a part of this disease progression. Itching can definitely be seen with some of the skin conditions associated with lupus (or possibly Sjogrens as well), but it should be relatively straightforward to distinguish between these three conditions on the basis of laboratory testing (and sometimes imaging studies to evaluate the liver). There are some types of rheumatologic diagnosis that represent an overlap syndrome and have features of several distinct disorders, but again, this should only be determined after a thorough evaluation including multiple laboratory studies.
It sounds like you may need to revisit a rheumatologist for a thorough review of your extensive history, your current complaints and physical exam, any testing records that might be available over the last 10 years, and then the results of a fresh round of investigation. Hopefully this will help arrive at a correct diagnosis as well as suggest possible treatment options. The disease course and prognosis for the three conditions you mentioned are also quite different, and it will be important for you to have all of the information you need about the correct diagnosis.