Dermatomyositis clinical features

Tazelaar HD, Viggiano RW, Pickersgill J, et al. Interstitial lung disease in polymyositis and dermatomyositis. Clinical features and prognosis as correlated with histologic findings. Am Rev Respir Dis 1990 141 727-733. 

Fujisawa T, Suda T, Nakamura Y, et al. Differences in clinical features and prognosis of interstitial lung diseases between polymyositis and dermatomyositis. J Rheumatol 2005 32 58-64. 

Juvenile dermatomyositis (JDM) is perhaps the most uniform, in terms of clinical and histopathological features, of the whole PM/DM disease complex. Presentation may be before 5 years of age with peak incidence between 8 and 12 years. The disease may remit and recur until well into young adult life. The skin lesions include a facial rash in butterfly distribution across nose and cheeks. Erythematous skin changes are seen over extensor surfaces of joints, especially knees, knuckles and elbows. Muscle involvement is generally evident some time later and takes the form of weakness and stiffness, particularly affecting shoulder and pelvic musculature. Proximal muscles are often worse affected than distal muscles and extensors worse than flexors. In the absence of prompt and effective treatment contractures may occur at elbows, ankles, knees, and hips. Subcutaneous calcification and skin ulceration may be found calcification of deeper-lying connective tissue may be apparent on X-ray. 

According to Verity et al.,43 the described pathologic changes in skin, fascia, and muscle, along with the defined clinical syndrome of EMS, allow for an accurate differentiation from related syndromes, including eosinophilia polymyositis, scleroderma, idiopathic polymyositic/dermatomyositis, polyarteritis nodosa, and toxic oil syndrome.43 A few reports have considered the comparison of the histopathologic features of Shulman s syndrome (diffuse fasciitis with eosinophilia) and the fasciitis associated with EMS.43... 

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