Nailfold capillaroscopic changes in dermatomyositis and polymyositis

Area of Science:

• Rheumatology
• Dermatology
• Neurology

Background:

• Inflammatory myopathies (IM) encompass a spectrum of muscle diseases affecting both children and adults.
• Nailfold videocapillaroscopy (NVC) alterations are recognized in IM, but data comparing polymyositis (PM) and dermatomyositis (DM) are inconsistent.
• Existing research shows discrepancies in NVC findings between PM and DM, necessitating further investigation.

Purpose of the Study:

• To delineate the specific capillaroscopic differences between patients diagnosed with polymyositis (PM) and dermatomyositis (DM).
• To explore potential correlations between NVC findings and the clinical and serological characteristics of IM patients.
• To compare NVC findings in IM patients with those in primary Raynaud's phenomenon for reference.

Main Methods:

• A cross-sectional study was conducted over six months, analyzing 52 unselected IM patients (29 DM, 23 PM).
• Nailfold videocapillaroscopy (NVC) was performed, and findings such as tortuosities, capillary loss, enlarged/giant capillaries, microhemorrhages, and ramified capillaries were semiquantitatively scored.
• Vascular array disorganization, avascular areas, and scleroderma patterns were assessed, and results were compared with 52 primary Raynaud's phenomenon patients.

Main Results:

• NVC alterations, including vascular disorganization, enlarged/giant capillaries, capillary loss, and scleroderma-like patterns, were predominantly observed in IM patients.
• Dermatomyositis (DM) patients exhibited significantly more frequent and severe NVC changes compared to polymyositis (PM) patients.
• In DM, reduced capillary density and more frequent giant capillaries were associated with disease duration of 6 months or less, suggesting early microangiopathy.

Conclusions:

• Nailfold videocapillaroscopy reveals distinct capillaroscopic alterations in inflammatory myopathies, primarily in dermatomyositis, indicative of diffuse microangiopathy.
• More severe NVC changes in DM patients correlate with shorter disease duration, highlighting the early onset of vascular abnormalities.
• The study identified specific NVC patterns that differentiate DM from PM and suggests NVC as a valuable tool for assessing disease activity and progression in IM.