Dermatomyositis

Dermatomyositis

Dermatomyositis is a rare inflammatory myopathy with characteristic skin manifestations and muscular weakness. The disease can be categorized as adult idiopathic, juvenile, or amyopathic dermatomyositis as well as that associated with a connective tissue disease or a malignancy. Immunologic factors are most likely involved in the pathogenesis of the disease; however, genetic and environmental issues may also play important roles. Treatment with immunosuppressive agents has proved successful in the majority of patients, although significant morbidity still occurs.

Vesiculo-bullous dermatomyositis

Cutaneous manifestations of dermatomyositis (DM) commonly include Gottron's papules, cuticular erythema and telangiectasia, periorbital edema with a "heliotrope" rash, a papulosquamous eruption of the hairline, face, and trunk, as well as poikiloderma. Very few references can be found concerning vesicular and bullous lesions, however. We present two patients with dermatomyositis who manifested vesicular and bullous lesions who were initially misdiagnosed. Although rare, it is important to recognize this form of DM to avoid misdiagnosis. Furthermore, in some cases, vesiculo-bullous DM may portend a poor prognosis.

Cutaneous photosensitivity in dermatomyositis

The incidence and nature of cutaneous photosensitivity were studied in 10 patients suffering from dermatomyositis. Five reported an abnormality, which consisted of photoaggravation of preexisting cutaneous lesions in three, and abnormal transient erythemal responses in two. Monochromatic irradiation testing of all 10 patients demonstrated reduced minimal erythemal doses in two, at 307.5 nm, and at 340 and 360 nm, respectively; only the latter individual had clinical light sensitivity. Exposure to low-dose, solar-simulated radiation of the unaffected skin of the former patient, and five others who agreed to the procedure, three of whom complained of light sensitivity, induced a lesion with the clinical and immunofluorescence characteristics of dermatomyositis in only the first one. Four other patients replied to a mailed questionnaire, and three of these reported aggravation of their rash and provocation of new lesions by sunlight. Photosensitivity may thus be an important cutaneous feature of dermatomyositis.

Cutaneous changes of dermatomyositis in patients with normal muscle enzymes: dermatomyositis sine myositis?

BACKGROUND

Dermatomyositis sine myositis may have various connotations. Controversy exists as to nomenclature, degree of evaluation required, therapy, and course (e.g., does true dermatomyositis of the skin only exist?).

OBJECTIVE

The purpose of this study was to assess prospectively patients with the clinicopathologic features of dermatomyositis and normal muscle enzyme serum levels to determine their course in terms of the onset of muscle disease.

METHODS

Thirteen patients were studied by complete history and clinical examination, laboratory studies, electromyography, and skin and muscle biopsy. They were observed for 1 to 6 years.

RESULTS

Patients were classifiable into three groups: (1) cutaneous changes only, (2) cutaneous changes only at baseline with subsequent development of myositis, and (3) cutaneous changes with normal muscle enzyme serum levels at baseline but with myositis demonstrated by electromyography and/or muscle biopsy specimens.

CONCLUSION

Significantly different prognostic and therapeutic implications are present in patients with dermatomyositis with normal muscle enzyme serum levels depending on the results of electromyography, muscle biopsy, and clinical observation.

Cutaneous changes of dermatomyositis precede muscle weakness

A retrospective review of 50 patients with dermatomyositis was performed to determine the temporal relationship between onset of muscle weakness and skin involvement. We found that cutaneous changes sometimes preceded muscle weakness more than a year before the onset of muscle weakness. These findings suggest that the characteristic dermatomyositis eruption without muscle weakness should not preclude a diagnosis of dermatomyositis, and these cases should be carefully followed.

Dermatomyositis and female malignancy

Six female patients, all with dermatomyositis (DM) and malignancy, have been evaluated and followed over a period of up to 6 years. Five patients had malignancy prior to the diagnosis of DM. Two of these five patients had uterine endometrial adenocarcinoma and another two patients had cervical carcinomas (one each adenocarcinoma and squamous cell carcinoma), and one had adenocarcinoma of the breast. In these five patients there was no evidence of malignancy at the time of diagnosis of DM. One of these five patients had an additional primary malignancy (adenocarcinoma of the breast) which complicated her course. An ovarian adenocarcinoma was present in the sixth patient. The ovarian carcinoma was discovered because of progressive cutaneous disease, and resection and chemotherapy led to a partial control of the DM. The patient with adenocarcinoma of the cervix developed metastases which were discovered when the DM became resistant to therapy. Although DM can parallel the course of a malignant disease, this was not generally the case in this group of patients.

Discordance of skin and muscle involvement in dermatomyositis

The skin manifestations of dermatomyositis infrequently occur without the myositis. A 24-year-old woman presented with concordance of the skin and muscle components of dermatomyositis, followed by a remission of the myositis with a persistence of significant rash for 17 years, finally presenting with a flare of both skin and muscle components together. Clinicians should be alert to the recurrence of an underlying myositis at any time.

Cutaneous lesions of dermatomyositis are improved by hydroxychloroquine

Dermatomyositis (DM) is a collagen vascular disease with prominent cutaneous findings. Although the myositis often responds to therapy with corticosteroids and/or immunosuppressives, the cutaneous disease may not respond. Seven patients with cutaneous lesions of DM that had not responded to therapy were treated with hydroxychloroquine in an open study. Three patients had idiopathic DM, one had DM without myositis, one had DM with malignancy, and one had adolescent DM. The response to the addition of hydroxychloroquine was good in all of the patients, and three had total resolution of their skin lesions. In two patients the corticosteroid dosage could be tapered. Therapy with hydroxychloroquine did not appear to have any beneficial effect on the myositis. We conclude that hydroxychloroquine may have a role as an adjuvant to the therapy of patients with cutaneous lesions of DM.