Objective: To explore the clinical features and prognosis of clinically amyopathic dermatomyositis (C-ADM).
Methods: The clinical data, including skin lesion, muscle involvement, and lung disease, of 29 patients with C-ADM, 6 males and 23 females with a male/female ratio of 1:3.83, aged 44 +/- 8, were analyzed. Skin biopsy was taken in 5 patients and lung HRCT was done in all the patients.
Results: The mean age at onset was (44 +/- 8) years. All patients presented with characteristic skin lesions such as Gottron's papulae (91.3%); heliotropic periorbital erythremia (75.9%); V-sign rash (37.9%); shawl-sign rash (24.1%); and periungual erythema and telangiectasias (20.7%). Gottron's papule was most commonly seen on the dorsal aspect of elbow (86.2%), proximal interphalangeal joints (58.6%), metacarpophalangeal joints (48.3%), patellae (23.8%), hip (20.7%), shoulder (13.8%), and ankle (9.5%). The cutaneous histopathologic pictures of these patients were all compatible with the skin lesions of dermatomyositis. Interstitial lung disease (ILD) was found by lung HRCT in 19 patients (65.5%). All patients received steroids combined with immunosuppressants, but rapidly progressive ILD happened to some of the patients and finally led to death due to respiratory failure in 5 of them.
Conclusion: C-ADM is most commonly seen in the middle-aged women. ILD is the commonest respiratory problem arising in C-ADM patients and can be fatal, therefore should be properly treated.