Sjögren’s syndrome (SS) is a chronic inflammatory disorder characterized by diminished lacrimal and salivary gland function. SS occurs in a primary form not associated with other diseases and in a secondary form that complicates other rheumatic conditions. The most common disease associated with secondary SS is rheumatoid arthritis.
In primary or secondary SS, decreased exocrine gland function leads to the “sicca complex,” a combination of dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia) [1,2]. In addition, a variety of other disease manifestations can occur in SS. The clinical manifestations of SS are divided into the exocrine gland features and the extraglandular disease features .
An effective classification system for SS must accommodate the range of clinical manifestations of this disorder. The ends of the clinical spectrum of SS are diverse:
- At the severe end are patients with florid salivary gland enlargement, adenopathy, antibodies to the Ro/SSA and La/SSB antigens, cryoglobulinemia, hypocomplementemia, a propensity to develop non-Hodgkin lymphoma, and other extraglandular disease manifestations.
- At the mild end are patients with moderate symptoms of dry eyes, dry mouth, a low titer of antinuclear antibody, and vague symptoms of fatigue, myalgias, and cognitive dysfunction. In many patients with mild disease, distinguishing SS patients from individuals with fibromyalgia or depression who have ocular and/or oral dryness caused or exacerbated by medications with anticholinergic side effects is a major challenge.
- Another group of patients with extraglandular manifestations may be found to have antinuclear antibody and Ro/SSA antibody during evaluation, even though they lack dominant manifestations of dry eyes or dry mouth. These laboratory findings may be found during evaluation of neuropathies, nephropathies, hematologic abnormalities, or lymphoproliferative involvement of other organs with a pattern suggestive of SS or of systemic lupus erythematosus in the extraglandular organs.
This topic will review the classification, diagnosis, and epidemiology of SS. The clinical manifestations, pathogenesis, treatment, and prognosis of this disorder are discussed separately. (See "Clinical manifestations of Sjögren's syndrome: Exocrine gland disease" and "Clinical manifestations of Sjögren's syndrome: Extraglandular disease" and "Pathogenesis of Sjögren's syndrome" and "Treatment of dry eyes in Sjögren's syndrome" and "Treatment of dry mouth and other non-ocular sicca symptoms in Sjögren's syndrome" and "Treatment of systemic and extraglandular manifestations of Sjögren’s syndrome".)