Clinical Characteristics of Sarcoid Arthropathy: A Population-Based Study

Objective The epidemiology and clinical characteristics of sarcoid arthropathy are not well described, as only referral-based studies have been reported. This study aimed to use the data from a geographically well-defined population to characterize the clinical characteristics of sarcoid arthropathy. Methods An inception cohort of patients with incident sarcoidosis in the years 1976-2013 in a geographically well-defined population was identified based on comprehensive individual medical records review. Inclusion required physician diagnosis supported by histopathology and radiologic features of intrathoracic sarcoidosis, compatible clinical presentation, and exclusion of other granulomatous diseases. Patients with joint pain were then identified from this cohort. Results In 1976-2013, all 345 incident cases of sarcoidosis were identified. Symptoms of joint pain occurred in 42 patients (mean age 41.2 years, 57.1% female, and 95% white), and 35 patients had swollen joint(s) on physical examination. Most patients had arthralgia prior to the diagnosis of sarcoidosis, with an average time to diagnosis of 21 days. Of the 35 cases, oligoarthritis (2 to 4 joints) was the most common pattern (88% of cases), followed by monoarthritis (6%) and polyarthritis (6%). Ankles were involved in 91% of cases. In the majority of patients (88%), the arthritis resolved within 6 weeks. Classic Lofgren's syndrome was observed in 11 patients (26%). Conclusion Inflammatory arthritis occurs in a minority of patients with sarcoidosis. Acute oligoarthritis with bilateral ankle involvement was the most common pattern of sarcoid arthropathy. It should be noted that the generalizability of the results may be limited, as the cohort was predominantly white.