Dermatomyositis



Dermatomyositis


Ruth Ann Vleugels and Jeffrey P. Callen


Evidence Levels:  A Double-blind study  B Clinical trial ≥ 20 subjects  C Clinical trial < 20 subjects  D Series ≥ 5 subjects  E Anecdotal case reports


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Dermatomyositis (DM) is one of the idiopathic inflammatory myopathies characterized by cutaneous disease, including a heliotrope eruption, Gottron papules, a violaceous erythema on extensor surfaces in a photodistribution pattern, and/or periungual changes. Patients with cutaneous lesions of DM often have weakness of the proximal muscles, elevated enzymes such as creatine kinase or aldolase, or abnormal electromyograms or muscle biopsy findings. Some, however, have cutaneous disease that either precedes the onset of demonstrable muscle disease or occurs in its absence. In addition, many patients have persistent cutaneous manifestations long after their muscle disease is adequately controlled. DM in children and adolescents may be complicated by calcinosis, particularly when treatment is delayed. Adults with DM have a greater risk of having or developing a malignancy, usually within the first 3 years following diagnosis.



Management strategy


Prior to treatment the patient should be thoroughly evaluated to assess the severity of the disease, the presence of systemic involvement such as pulmonary, cardiac, or gastrointestinal involvement, and the presence of malignancy.


The goal of management is to reverse the weakness and allow the patient to return to normal functional status. The prevention of contractures is also a consideration, and the prevention or treatment of calcinosis is usually an issue in the management of children and adolescents, but may occur rarely in adults as well. Patients with cutaneous disease are troubled by intense pruritus and the appearance of their skin, and therefore request management even when the muscle disease has been effectively treated or is absent.


For the myopathy, systemic corticosteroids with or without an immunosuppressive agent are the standard treatment. Most patients respond to these agents, but for those who do not, high-dose intravenous immunoglobulin may be of benefit. Patients with cutaneous disease are photosensitive and are treated with sunscreens and behavior modification, topical corticosteroids, and occasionally topical calcineurin inhibitors, oral antimalarials, and often an oral immunosuppressant. High-dose intravenous immunoglobulin may also be used for recalcitrant cutaneous disease. Ultimately, the therapeutic goal is to provide patient relief from the cutaneous inflammation and associated symptoms utilizing a combination of topical and/or systemic medications selected after considering a patient’s comorbidities.


One of the problems with many of the reports published to date regarding therapeutic options for cutaneous DM is the lack of the use of a validated measure of activity to assess the activity of skin disease and response to therapy. To this end there are three measures that have recently been developed: the Dermatomyositis Skin Severity Index (DSSI) (Br J Dermatol 2008; 158: 345–350), the Cutaneous Dermatomyositis Area and Severity Index (CDASI) (Arch Dermatol Res 2008; 300: 3–9, and Br J Dermatol 2012; 162: 669–673), and a cutaneous assessment tool in juvenile dermatomyositis (Arthritis Rheum 2008; 59: 352–356). Unfortunately, none of these measures is routinely used in studies investigating therapeutic interventions for DM; however, the tools are being utilized more frequently and will ideally become incorporated as standard practice in the future as a means to assess cutaneous disease response.



Specific investigations













The value of malignancy evaluation in patients with dermatomyositis.

Callen JP. J Am Acad Dermatol 1982; 6: 253–9.


DM has been linked to internal malignancy in adults, but the value of an extensive malignancy evaluation in patients with DM is controversial. Fifty-seven patients who had DM with malignancies for whom data were available regarding the discovery of malignancy have been analyzed: 53 of these were reported previously. There were 67 malignancies in the 57 patients. The malignancy preceded (26 cases), followed (23 cases), or occurred with the DM (18 cases). A ‘blind’ (non-directed) malignancy search was not of value in any of the cases analyzed. Rather, the tumors were discovered in 40 cases by history (preceding tumor or abnormal symptoms), in 14 cases by physical examination, and in 12 cases by abnormal laboratory findings (e.g., chest radiograph, urinalysis, stool guaiac). One case was not discovered until autopsy (adenocarcinoma of the broad ligament). Analysis of tumor sites further negates the value of a malignancy work-up because most tumors (>90%) occur in areas not amenable to a ‘routine malignancy search.’ In several instances patients had an extensive search without having a complete physical examination.


Malignancy evaluations should be directed by abnormalities found on history, physical findings, or routine laboratory testing. However, since this paper was published, new, less invasive methods of malignancy search have been developed, and therefore the initial search should include CT scans of the chest, abdomen, and pelvis in most patients, and these scans should be repeated annually for at least 3 years. Malignancy screening should also include annual physical examinations.




A new approach to the classification of idiopathic inflammatory myopathy: myositis-specific autoantibodies define useful homogeneous patient groups.

Love LA, Leff RL, Fraser DD, Targoff IN, Dalakas M, Plotz PH, et al. Medicine (Baltimore) 1991; 70: 360–74.


This study compared the usefulness of myositis-specific autoantibodies (anti-aminoacyl-tRNA synthetases, anti-signal recognition particle [anti-SRP], anti-Mi-2, and anti-MAS) to the standard clinical categories (polymyositis, DM, overlap myositis, cancer-associated myositis, and inclusion body myositis) in predicting clinical signs and symptoms and prognosis in 212 adult patients. Compared to those without these antibodies, patients with anti-aminoacyl-tRNA synthetase autoantibodies (n = 47) had significantly more frequent arthritis, fever, interstitial lung disease, and ‘mechanic’s hands’; higher mean prednisone dose at survey; higher proportion of patients receiving cytotoxic drugs; and higher death rates. Those with anti-SRP antibodies (n = 7) had more frequent palpitations, myalgias, severe refractory disease, and higher death rates. Patients with anti-Mi-2 antibodies (n = 10) had increased ‘V-sign’ and ‘shawl-sign’ rashes and cuticular overgrowth, as well as a good response to therapy. These findings suggest that myositis-specific autoantibody status is a more useful guide than clinical group in assessing patients with myositis.


These antibodies are less common in patients with DM than in patients with polymyositis, and currently only the anti-amino-acyl-tRNA synthetase autoantibodies are frequently incorporated into clinical practice.



Clinical correlations with dermatomyositis-specific autoantibodies in adult Japanese patients with dermatomyositis: a multicenter cross-sectional study.

Hamaguchi Y, Kuwana M, Hoshino K, Hasegawa M, Kaji K, Matsushita T, et al. Arch Dermatol 2011; 147: 391–8.


In this study of 376 adult Japanese patients with DM, anti-CADM-140 autoantibodies were associated with clinically amyopathic DM and rapidly progressive interstitial lung disease, whereas anti-155/140 autoantibodies were associated with malignancy. Anti-Mi-2 autoantibodies were associated with classical DM without either malignancy or pulmonary disease. The authors note that these autoantibodies define distinct clinical subsets and therefore are useful in predicting patient outcomes in DM.


The anti-CADM-140 and anti-155/140 autoantibodies are considered investigational at present and are not routinely available in commercial laboratories. They may, however, alter the screening practices for patients with DM in the future.


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Aug 7, 2016 | Posted by in Dermatology | Comments Off on Dermatomyositis

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