Characteristics of DM and PM subgroup as per ACR/EULAR criteria
| DM (n=14) | PM (n=12) | |
| Mean age in years±SD | 46.3±12.8 | 40.3±10.8 |
| Median time to diagnosis in months (IQR) | 8 (6.2–9.7) | 2 (1–3) |
| Female:male | 11:3 | 6:6 |
| Organ system involved | 14 | 12 |
| Muscle | 14 | 7 |
| Cutaneous | 13 | 11 |
| Constitutional | 11 | 6 |
| Skeletal | 4 | 10 |
| Gastrointestinal | 8 | 8 |
| Pulmonary | 5 | 3 |
| Severity of myositis at onset | ||
| Mild | 2 | 1 |
| Moderate | 0 | 0 |
| Severe | 12 | 11 |
| Cutaneous manifestations | ||
| Heliotrope rash | 5 | na |
| Gottrons papule | 4 | na |
| Gottrons sign | 11 | na |
| Non-specific rash | 6 | 7 |
ACR/EULAR, American College of Rheumatology/European League Against Rheumatism; DM, dermatomyositis; na, not applicable; PM, polymyositis.