Musculoskeletal involvement in systemic sclerosis.

Musculoskeletal involvement is more frequent than expected in patients with systemic sclerosis (SSc) and is a major cause of disability, even if the prognosis of the disease largely depends on visceral involvement. The most common clinical feature of musculoskeletal involvement is arthralgia; less frequent features are arthritis, flexion contractures, stiffness (affecting predominantly fingers, wrists and ankles), proximal muscle weakness (mainly of the shoulder and hip) and tendon sheath involvement. Tendon friction rubs are predictive of poor prognosis. If musculoskeletal involvement is suspected, serum creatinine phosphokinase, aldolase, lactate dehydrogenase, alkaline phosphate, rheumatoid factor and anticyclic citrullinated peptide autoantibodies should be checked routinely. Treatment for muscle involvement has not yet been considered adequately and, in the future, it is to be hoped that clinical trials will identify new drugs to control this aspect of SSc, which seriously compromises patients' quality of life.