Dermatomyositis: nailfold capillaroscopy patterns and a general survey.

Introduction: Dermatomyositis (DM) is a group of autoimmune idiopathic inflammatory myopathies characterized by typical cutaneous signs and symptoms of muscle involvement. The diseases can be associated with cancer in the paraneoplastic syndrome, calcinosis, interstitial lung disease, other autoimmune connective tissue diseases (in overlap syndrome), and Raynaud's phenomenon.

Methods: Clinical and capillaroscopic data were gathered from 43 patients with DM. The diagnosis was based on the Bohan‒Peter and European League against Rheumatism / American College of Rheumatology (EULAR/ACR) classification criteria. In addition, nailfold capillaroscopy was performed in all patients.

Results: In our cohort, eight patients had overlap syndrome, six had paraneoplastic syndrome, eight presented with interstitial lung disease, and nine had calcinosis, two of whom also had a cancerous pathology. Raynaud's phenomenon was reported in 74% of patients. Upon nailfold capillaroscopy, 84% of patients presented giant capillaries, 81% ramified capillaries, and 70% both. The latter, notably giant ramified capillaries, could be considered specific for DM. The detection of prominent subpapillary venous plexuses was associated with pulmonary involvement. In contrast, alterations of the pericapillary spaces were associated with the severity and prognosis of DM.

Conclusions: Our results underline the usefulness of nailfold capillaroscopy in the diagnosis and prognosis of DM. Based on the results and literature data, specific nailfold capillaroscopy features should be included in DM diagnostic criteria.