Overlap syndromes

Overlap syndromes refers to a group of conditions that have clinical features of, and meet classification criteria for, more than one well-characterised rheumatic disease.

The spectrum of overlap syndromes includes mixed connective tissue disease (MCTD); antisynthetase syndrome; and polymyositis/scleroderma (PM/Scl) overlap syndrome.

MCTD is a distinct clinical entity characterised by overlapping features of systemic lupus erythematosus, scleroderma, myositis, and rheumatoid arthritis in the setting of a high titre of auto-antibodies to U1 ribonucleoprotein.

Antisynthetase syndromes form a distinct group characterised by antibodies directed against various aminoacyl-tRNA synthetase enzymes with overlapping clinical features of myositis, arthritis, and interstitial lung disease.

PM/Scl syndrome is characterised by overlapping features of scleroderma and polymyositis, PM/Scl antibody, Raynaud's phenomenon (RP), tendon inflammation, and interstitial lung disease.

Treatment of overlap syndromes is tailored to the active clinical manifestations and ranges from supportive therapy to cytotoxic immunosuppressive regimens.

'Overlap syndromes' refers to a diverse group of conditions that have clinical features of, and meet classification criteria for, more than 1 well-characterised rheumatic disease. They usually present subacutely with clinical manifestations that can include different organ systems. The pattern of organ involvement reflects the characteristic features of the well-defined rheumatic diseases occurring together.