Seronegative Sicca Syndrome: Diagnostic Considerations and Management Strategies

Seronegative sicca syndrome encompasses patients who present with xerostomia and/or keratoconjunctivitis sicca but lack anti-SSA/SSB antibodies and do not fulfill current classification criteria for primary Sjögren's syndrome (pSS). Despite symptom overlap with pSS, these individuals remain diagnostically and therapeutically unclassified. This review studies the clinical, immunological, and pathological spectrum of seronegative sicca, highlighting its heterogeneity and the limitations of antibody-centric diagnostic frameworks. Histopathologic findings in some seronegative patients-including focal lymphocytic sialadenitis-mirror those seen in pSS, suggesting underlying immune-mediated glandular damage. In others, nonspecific or normal biopsy findings suggest non-immune mechanisms. New evidence of immune activity, such as elevated cytokines (BAFF, IFN-α), and novel autoantibodies (SP-1, CA-VI), further supports the concept of subclinical autoimmunity in a subset of these patients. Clinically, they often face significant burden, including dryness, fatigue, and pain, yet remain excluded from most research cohorts, therapeutic trials, and clinical guidelines. Their management is often individualized, relying on symptomatic therapies rather than immunomodulatory agents. The lack of validated diagnostic criteria and prognostic markers compounds the uncertainty surrounding disease evolution, as some patients may later seroconvert or develop systemic features. To address these gaps, a paradigm shift is needed-one that embraces the spectrum of sicca syndromes, incorporates advanced immunophenotyping, and allows inclusion of seronegative patients in research and care algorithms.