The patient was started on methotrexate 20 mg weekly, folic acid 800 mcg daily, and clobetasol and desonide corticosteroid creams on the affected areas of the skin. When his symptoms flared, he was restarted on prednisone 5 mg twice a day for a few weeks.
The patient tried to continue football and school but he was unable to do so, and he took a medical leave of absence. His myalgias are improved month by month. His hair grew back, but his rash is improving much slower.
Dermatomyositis is an idiopathic myopathy with characteristic skin findings. Symptoms may include pruritic rash on exposed skin surfaces, hair loss, and proximal muscle weakness (difficulty combing hair, climbing stairs). Muscles usually are not tender on exam.
On physical exam, the clinician may find the characteristic periorbital heliotrope rash (named after the violet-colored flower) and Gottren’s papules on the MCPs, PIPs and DIPs. Also, the patient may have a malar rash, poikloderma, violaceous erythema on extensor surfaces, or periungal / cuticular changes.
Labs can reveal an elevated CK, aldolase, LD, and AST. Myositis specific antibodies are present in 30% of patients (ANA, Anti-Mi-2, specific, not sensitive for dermatomyositis), Anti-Jo-1 (more common in polymyositis).
Consider MRI if you are suspicious for inflammatory myopathy. Chest x-ray, EMG, and muscle biopsy can also be a part of the work-up.
Complications include cardiopulmonary involvement. Calcinosis can occur and is seen more frequently in children. There is an association with malignancy more often if age > 60.
Treatments options for myalgia include corticosteroids and immunosuppressive agents. For the skin manifestations, sun avoidance, sunscreens, topical corticosteroids, antimalarial agents, methotrexate, IVIG are all available therapies.
With treatment, remission is seen in 20%. 5% have a progressive course resulting in death. Many do not recover completely, and have residual weakness or other sequelae.
Dermatomyositis is a disease process of unknown etiology. Due to the wide array of signs and symptoms, it is often difficult to diagnose and can be confused with other disease processes, such as systemic lupus erythematosus and other collagen vascular disorders, contact dermatitis, and HIV. Dermatomyositis can often be distinguished from other diseases by the characteristic cutaneous findings, as mentioned by the author. Initiating early therapy is important to improving function and preventing further disability. Prednisone is the first-line medication, with methotrexate as adjunctive therapy. Delays in treatment can lead to further morbidity and even mortality.
Callen JP. Dermatomyositis. EMedicine Rheuamtology. Updated 1/7/11. Accessed 2/28/11. http://emedicine.medscape.com/article/332783-overview.
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