Sarcoid and erythema nodosum arthropathies.

Sarcoidosis is a systemic granulomatous disease of unknown origin, characterized in affected organs by an accumulation of activated T lymphocytes and macrophages. Musculoskeletal manifestations of sarcoidosis include acute and chronic arthritis and muscular and osseous sarcoidosis. In certain populations, acute sarcoidosis often presents with constitutional symptoms, polyarthritis and erythema nodosum (Löfgren's syndrome). Erythema nodosum, often with joint symptoms, also occurs in association with several other conditions including infections, medications and other underlying diseases. The diagnosis of sarcoidosis should be based on a tissue biopsy, but a patient with typical Löfgren's syndrome may not require biopsy proof. Among the long list of biochemical markers that have been suggested as aids for diagnosis and monitoring of sarcoidosis, calcium in serum and urine and angiotensin-converting enzyme in serum are well-established clinical tools. Serum angiotensin-converting enzyme can be used for monitoring disease activity in the individual patient, but because of lack of sensitivity and specificity its diagnostic value is rather low. Non-steroidal anti-inflammatory agents usually effectively alleviate acute sarcoid arthritis and joint symptoms associated with erythema nodosum. In severe acute arthritis and in chronic arthritis, corticosteroids may be required to control the symptoms. In patients requiring persistent corticosteroid therapy, antimalarial agents and methotrexate constitute therapeutic alternatives.