Table 1.
Dermatomyositis Definitions
| Type of Dermatomyositis | Definition |
|---|---|
| Classic (CDM) | Hallmark cutaneous manifestations with evidence of proximal muscle weakness occurring within 6 mo after onset of skin disease |
| Amyopathic (ADM) | Hallmark cutaneous manifestations of dermatomyositis for >6 mo without clinical or laboratory evidence of myopathy |
| Exclusion criteria: | |
| 1) Use of drugs capable of producing hallmark cutaneous changes characteristic of dermatomyositis | |
| 2) Use of systemic immunosuppressive agents for >2 consecutive mo within the 6 mo after skin disease onset | |
| Hypomyopathic (HDM) | Hallmark cutaneous manifestations without subjective muscle weakness for >6 mo but with objective evidence of subclinical muscle weakness on further testing (abnormal muscle enzymes, signs of myopathy on electromyography or muscle biopsy) |
| Clinically amyopathic (CADM) | A term used to describe both ADM and HDM |
| Clinically amyopathic evolving into classic (CADM→CDM) | Patients with cutaneous dermatomyositis with onset of muscle involvement >6 mo after onset of clinically significant skin disease |
| Juvenile (JDM) | Dermatomyositis of any subset occurring in a patient younger than 18 years |
Adapted from Gerami et al.13 Used with permission.