Introduction to Sjögren Syndrome in Children

Sjögren syndrome is a chronic, inflammatory, autoimmune disease characterized by progressive lymphocytic and plasma cell infiltration of the salivary and lacrimal glands.

Epidemiology.
Sjögren syndrome typically presents at 35–45 yr of age, with 90% of cases among women. It is uncommon in the pediatric age group. Sjögren syndrome can occur as an isolated disorder, referred to as primary Sjögren syndrome (sicca complex), or as a secondary form in association with other rheumatic disorders.

Etiology And Pathogenesis.
The etiology of Sjögren syndrome is complex and includes genetic predisposition, and possibly an infectious trigger. Lymphocytes and plasma cells infiltrate salivary glands, forming distinct periductal and periacinar foci that become confluent and may replace epithelial structure. This autoimmune exocrinopathy results in xerophthalmia (dry eyes, or keratoconjunctivitis sicca) and xerostomia (dry mouth). Several genes regulating apoptosis influence the chronicity of lymphocytic infiltration.

Clinical Manifestations.
International classification criteria for the diagnosis of Sjögren syndrome in adult patients have been developed, and diagnostic criteria in children have been proposed. Clinical manifestations are related to exocrine disease of the epithelial surfaces of the eyes, mouth, nose, larynx and trachea, vagina, and skin, leading to the common symptoms of photophobia, burning and itching eyes, blurred vision, painless unilateral or bilateral enlargement of the parotid glands, decreased sense of taste, dental caries, dysphagia, fissured tongue, and angular cheilitis. At the onset of the disease, recurrent parotid gland enlargement and parotitis is the most common manifestation in children, whereas sicca manifestations are most common in adults.

Positive antinuclear antibodies (ANAs) and articular manifestations are significantly more frequent in adults. Subjective symptoms of xerostomia are less frequent among juvenile cases, indicating that Sjögren syndrome is a slowly progressive disease.

Additional manifestations may include a decreased sense of smell, epistaxis, hoarseness, chronic otitis media, and internal organ exocrine disease involving the lungs, hepatobiliary system, pancreas, gastrointestinal tract, and kidneys.

Diagnosis.
The diagnosis is based on clinical features supported by biopsy of the lip or glands demonstrating foci of lymphocytic infiltration, cryoglobulinemia, elevated erythrocyte sedimentation rate (ESR), hypergammaglobulinemia, positive rheumatoid factor, and positive antinuclear antibodies to Ro(SSA) and La(SSB). Anti-?-fodrin autoantibodies, directed against an apoptotic cleavage product of ?-fodrin, are a useful diagnostic marker for juvenile Sjögren syndrome. The Schirmer test detects abnormal tear production (<5 mm of wetting of filter paper strip in 5 min). Imaging studies including MRI, technetium-99 scintigraphy, and sialography are useful in the diagnostic evaluation for Sjögren syndrome.

Treatment.
Symptomatic treatment includes the use of artificial tears, oral lozenges, and fluids to limit the damaging effects of decreased secretions. Corticosteroids, nonsteroidal anti-inflammatory drugs, and hydroxychloroquine are among the more commonly used agents for treatment. Greater potency immunosuppressive agents such as cyclosporine and cyclophosphamide are reserved for severe functional disorders and life-threatening complications.

Complications And Prognosis.
The symptoms of Sjögren syndrome develop and progress slowly. Diminished salivary flow typically remains constant for years. Because monoclonal B-lymphocyte disease originates chiefly from lymphocytic foci within salivary glands or from parenchymal internal organs, there is increased risk for mucosa-associated lymphoid tissue (MALT) lymphoma. Maternal Sjögren syndrome can be an antecedent to the neonatal lupus syndrome