To study the frequency and pattern of arthritis in primary Sjögren's syndrome (pSS), and its association with clinical and immunological factors.
102 patients with pSS diagnosed according to the preliminary European Classification Criteria were examined yearly for 4.5 years in a prospective study design. Arthralgia and arthritis were registered during the 459 patient-years observation period.
Arthralgia was reported by 75 patients (73.5%) and arthritis was demonstrated in 18 patients (17.6%) during the observation period. The most commonly affected joints were ancles (n = 7), MCP joints (n = 6), shoulders (n = 6), MTP joints (n = 6) and wrists (n = 5). Symmetrical bilateral arthritis were most commonly observed in ancles (4 patients) and wrists, shoulders and MTP joints. Five patients had longstanding arthritis observed at more than one clinical examination, and one developed seronegative rheumatoid arthritis. Arthralgia/arthritis was not correlated to any clinical or immunological factors, and usually ESR and CRP were normal when arthritis was observed.
Arthritis in pSS is usually mild, resolving, and unrelated to other clinical and immunological factors. A typical pattern is uni- and bilateral arthritis in the ankles, but joints in hands, feet and shoulders may also be affected.