Antisynthetase syndrome
In patients referred for polymyositis, it’s also important to evaluate for antisynthetase syndrome, Dr. Christopher-Stine said.
The arthritis seen in the extramuscular phenotype of the syndrome is rarely deforming, but despite what many physicians were taught, “it absolutely can be erosive,” she said.
In fact, 40% of people with this syndrome present with an isolated forme fruste seronegative rheumatoid arthritis, she said.
Roughening and desquamation of the skin on the radial surface of fingers or palms – a sign known as mechanic’s hands – that doesn’t have another identifiable cause suggests this diagnosis in patients with this type of arthritis, as does interstitial lung disease and Raynaud’s phenomenon.
The Raynaud’s can be “fairly significant in the sense that it is bothersome,” but it usually doesn’t lead to ulceration or digital necrosis.
This is different from what is seen with the scleroderma phenotype, she said, adding that “if you’re starting to see gangrene and digital loss, think of something else.”