What is the Difference between primary and secondary Sjogrens Syndrome?
• Primary SS is diagnosed in a patient with KCS who does not have another underlying rheumatic disease. Primary SS is immunogenetically associated with HLA-DRB1∗0301 and DRB1∗1501 and serologically associated with antibodies to Ro/SSA and La/SSB.
• Secondary SS is diagnosed in the presence of another rheumatic disease, most frequently rheumatoid arthritis (RA). The immunogenetic and serologic findings are usually those of the accompanying disease (e.g., HLA-DR4-positive if associated with RA).
Clinical manifestations such as dry eyes and mouth are similar in primary and secondary SS. Extraglandular features including parotid enlargement, lymphadenopathy, and lymphoma are more common in primary SS. The 2012 American College of Rheumatology (ACR) criteria do not distinguish between primary and secondary SS, while other criteria (2002 American-European Consensus Group [AECG]; 2016 ACR/European League Against Rheumatism [EULAR]) define primary and secondary SS separately.