The following is a summary of “Clinical characteristics and symptom progression of dermatomyositis subtypes: A retrospective analysis of a prospective database,” published in the July 2024 issue of Dermatology by Pandya, et al.

The characteristics of classic dermatomyositis (DM) and clinically amyopathic DM (CADM) are well documented, but the progression of these disease subtypes remains poorly understood. For a study, researchers sought to longitudinally monitor and characterize patients with classic DM and CADM who experience changes in their disease presentation over time.

They performed a retrospective review of prospectively collected data from a longitudinal database comprising 269 patients diagnosed with DM.

Among the patients, 51% had classic DM, and 49% had CADM. Notably, 40% of the classic patients with DM transitioned to postmyopathic DM (PmDM). The median Cutaneous Dermatomyositis Disease Area and Severity Index Activity (CDASI-A) score was lower in patients with PmDM than those with classic DM (13.0 vs 16.0). However, 45% of patients with PmDM had CDASI-A scores greater than 14. Additionally, 5% of patients with CADM developed muscle involvement over time. These patients initially had milder skin disease before the conversion to a more muscular presentation (median CDASI-A 12.0 vs. 16.0) and at the point of subtype conversion (median CDASI-A 9.0 vs 16.0). This study’s limitations included its retrospective nature and the fact that it was conducted at a single tertiary-care dermatology clinic.

About 40% of patients with classic DM transitioned to PmDM, with many continuing to have significant muscle and skin disease. The risk of CADM progressing to muscle disease is low, with the severity of skin disease potentially serving as a predictive factor for disease progression.

Reference: sciencedirect.com/science/article/abs/pii/S0190962224003128