The frequency of arthritis among patients with sarcoidosis is variously reported between 10% and 35%. It is usually acute in onset, but articular symptoms may appear insidiously and often antedate other manifestations of the disease. Knees and ankles are most commonly involved, but any joint may be affected. Distribution of joint involvement is usually polyarticular and symmetric. The arthritis is commonly self-limited, resolving after several weeks or months and rarely resulting in chronic arthritis, joint destruction, or significant deformity. Sarcoid arthropathy is often associated with erythema nodosum, but the diagnosis is contingent on the demonstration of other extra-articular manifestations of sarcoidosis and, notably, biopsy evidence of noncaseating granulomas. Despite the clinical appearance of an inflammatory arthritis, synovial fluid often is noninflammatory (ie, less than 2000 leukocytes/mcL). In chronic arthritis, radiographs show typical changes in the bones of the extremities with intact cortex and cystic changes.
Treatment of arthritis in sarcoidosis is usually symptomatic and supportive. Colchicine may be of value. Patients with severe and progressive joint disease may respond to corticosteroids or to TNF inhibitors.
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et al. Clinical characteristics of patients with bone sarcoidosis. Semin Arthritis Rheum. 2017 Aug;47(1):143–48.