Primary Sjögren's syndrome (pSS) in childhood is a rare disease. Diagnostic criteria are available for adult patients only. In order to establish diagnostic criteria for juvenile pSS an analysis of 7 girls and one boy suffering from pSS with early onset is reported. Due to the rarity of the disease, data on patients with pSS reported in the literature are included in the proposal for modified diagnostic criteria.
The diagnosis of pSS was established according to the criteria for adulthood pSS, duly modified, which include clinical symptoms and laboratory immunological evaluation.
The average age of our patients at clinical onset was 13.5 years (range: 10-17 yrs.). Clinical signs included systemic (fever, fatigue) as well as local (parotitis, vulvovaginitis, conjunctivitis) symptoms. Paralysis due to hypokalemia linked to renal tubular acidosis and central nervous system (CNS) involvement was seen in one patient. Asymptomatic renal tubular acidosis was diagnosed in another 2 patients. Autoimmune hepatitis was present in 2 patients. All patients had laboratory abnormalities: hyperimmunoglobulinemia IgG, high titers of antinuclear antibodies (anti-SS-A and/or anti-SS-B) and elevated serum amylases. Sicca syndrome was never seen during childhood, although it developed later in 3 patients, after 7 to 10 years of follow-up.
It has been stressed that the classical diagnostic criteria for adult Sjögren's syndrome, especially sicca syndrome, are not applicable to a pediatric onset of the disease. On the other hand, the presence of typical laboratory abnormalities can allow the diagnosis of these patients in the early stages. Both laboratory and clinical symptoms typical for childhood are included in our proposal for diagnostic criteria applicable to juvenile pSS. Life-threatening conditions such as hypokalemic paralysis, CNS involvement and hepatitis may also occur in children. Sicca syndrome tends to develop much later in pediatric patients.