Nailfold Videocapillaroscopy Alterations in Dermatomyositis and Systemic Sclerosis: Toward Identification of a Specific Pattern

Objective. The term scleroderma pattern typically defines capillary abnormalities of scleroderma spectrum disorders, mainly systemic sclerosis (SSc) and dermatomyositis (DM). Our study aimed to investigate differences in nailfold videocapillaroscopy (NVC) between DM and SSc, with a cross-sectional and longitudinal evaluation. Methods. NVC features of 29 consecutive patients with DM were compared with 90 patients with SSc categorized into the 3 subsets of scleroderma pattern: early, active, and late. Twenty patients with DM and all with SSc were also longitudinally reevaluated after 30 months of followup. Results. At baseline, all SSc groups showed giant capillaries, with significant differences with DM only for early and active pattern. Ramified capillaries were significantly more frequent and severe in DM than in early and active patterns, while DM showed an opposite trend compared with late pattern. Capillary loss was lower in early pattern and higher in active and late, compared with DM. Finally, giant-ramified capillaries were almost exclusive of DM. During followup, NVC showed a different evolution in DM and SSc. In DM we recorded a reduction of giant capillaries, while ramified capillaries increased both in DM and in early and active SSc pattern. The number of capillaries recovered in DM; conversely, capillary loss slightly worsened in all SSc patterns. Giant-ramified capillaries significantly decreased in patients with DM, remaining rare in patients with SSc. Conclusion. Our study strengthens the specificity of DM and SSc microangiopathy and points out the need for large prospective studies to confirm our results and possibly to revise current terminology by distinguishing between "scleroderma" and "dermatomyositis" patterns.