Clinically amyopathic dermatomyositis is being advocated as a distinct subcategory of dermatomyositis. When a patient exhibits the characteristic dermatomyositis rash without muscle symptoms, the following criteria should be considered:
- Skin manifestations typical of dermatomyositis: heliotrope rash, periorbital swelling, Grotton’s papules/sign, V-sign, shawl sign, holster sign
- Skin biopsy demonstrating reduced capillary density, deposits of membrane attack complex on small blood vessels along the dermal-epidermal junction, and within the walls of dermal blood vessels
- No objective weakness
- Normal serum creatine kinase (CK) levels
- Normal EMG findings
- Muscle biopsy, if done, does not reveal features compatible with definite or probable DM