Objective: To assess long-term outcome in patients with isolated keratoconjunctivitis sicca (KCS), primary Sjögren's syndrome (SS), and secondary SS.
Methods: In 112 patients referred because of dry eyes, an ophthalmologic diagnosis of KCS was made based on results of the Schirmer I test, the tear fluid lysozyme concentration, and rose bengal staining. Subsequent assessments, including sublabial salivary gland biopsy, were performed. Followup assessments were performed 10-12 years after initial diagnosis.
Results: Six patients were excluded because no biopsy specimen was available. Seventy-three percent of the remaining 106 patients were female, with a mean age of 53.5 years and a mean symptom duration of 3.9 years. Application of the 1987 classification criteria of Daniels and Talal revealed a diagnosis of isolated KCS in 56 patients, primary SS in 31, and secondary SS in 19. At baseline, 2 of 56 patients with isolated KCS and 8 of 31 with primary SS exhibited mild features of organ-specific autoimmune disease. At followup, 2 of 38 patients with isolated KCS and 4 of 21 with primary SS had developed new features related to autoimmune disease, not necessitating treatment with corticosteroids; none of the patients developed major glandular complications. Three of 30 patients with primary SS died of malignant lymphoma. In 1 of these patients, the possibility could not be excluded that sicca symptoms and infiltrates seen on sublabial salivary gland biopsy had occurred concomitantly with early stages of lymphoma. Malignant lymphoma did not develop in any of the patients with isolated KCS or secondary SS.
Conclusion: Primary Sjögren's syndrome is characterized by a stable and rather mild course of glandular and extraglandular manifestations, in marked contrast to the increased risk of development of malignant lymphoma in these patients. Since patients with isolated KCS do not have an increased risk for development of malignant lymphoma, a presumptive diagnosis of primary SS should be confirmed in patients with sicca syndrome.