Clinical and laboratory evaluation of sicca complaints: distinctive aspects of primary, secondary and non-Sjogren syndrome

Background Sjogren Syndrome (SS) is a systemic autoimmune disease with a wide spectrum of manifestations that can lead to misdiagnosis. This study describes and compares demographic, clinical, serological, and histopathological data from subjects with SS and non-Sjogren Syndrome (NSS). It also details specific features within the primary SS (pSS) and secondary SS (sSS) groups identifying sub-groups. Methods The sample included individuals referred to an academic medical center in Brazil for investigation of SS from 2012 to 2020. Patients were retrospectively classified as primary SS (pSS), secondary SS (sSS), or NSS, based on the American-European Consensus Group criteria (AECG-2002), after multi-professional clinical and laboratory evaluation. Results A total of 676 individuals were screened and 510 (75.4%) completed the assessments; 198 patients were classified as pSS, 149 as sSS, and 163 as NSS. Symptoms and glandular dysfunction tests were similar in the groups. Concerning pSS, extraglandular manifestations were present in 59% of patients; the elderly had more dry symptoms and peripheral neurological disorders; and 2.5% developed non-Hodgkin lymphoma. In sSS, each overlap promoted distinct clinical and laboratory variants. Several alternative diagnoses were identified as a cause of sicca complex in NSS group. Conclusions The diagnosis of SS remains a challenge behind dryness. Up to 31% of the suspected cases had other conditions associated to the symptoms. Histopathological analysis of LSG and SSa determined the diagnostic. Aging in pSS and overlap disease in sSS were responsible for distinct phenotypes and characteristic sub-groups in SS.