Assessment of nail fold capillary changes by hand-held dermoscopy in adult dermatomyositis: A single-centre prospective study.

Background: Hand-held dermoscopy is a valuable tool for dermatologists, but it has been rarely used to assess the nail fold capillary (NFC) in patients with dermatomyositis (DM).

Methods: Patients were collected from the Department of Dermatology and Venereology from July 2020 to July 2021, and the follow-up was conducted until January 2022. Demographic features, disease activity and NFC changes were analysed using a hand-held dermoscopy.

Results: The most common NFC finding in our study was bushy capillary (87.0%). There was no significant improvement in scleroderma-dermatomyositis (SD)-like nail fold changes or enlarged capillaries from baseline to 12 weeks of treatment (p > 0.05) or from 12 weeks to 24 weeks of treatment (p > 0.05), but there was a significant improvement from baseline to 24 weeks of treatment (p < 0.05). The avascular area did not improve from baseline to 12 weeks of follow-up, but the changes were significant from 12 weeks to 24 weeks of treatment (p < 0.05) and baseline to 24 weeks of treatment (p < 0.05). Periungual erythema improved significantly from baseline to 12 weeks of treatment (p < 0.05) and baseline to 24 weeks of treatment (p < 0.05), but it did not improve significantly from 12 weeks to 24 weeks of treatment (p > 0.05). There was no significant difference in disease activity between patients with or without specific NFC changes. However, some NFC features improved as disease activity decreased.

Conclusion: Dermoscopy of NFC is a cost-effective option for the preliminary diagnosis of DM. Further, long-term follow-up is necessary to study the relationship between disease activity and NFC changes.