Figure 1. The eyelids and cheeks are erythematous in a butterfly pattern.
Figure 2. Typical Gottron papules are present over the knuckles.
Figure 3. Periungual telangiectasia, typical of dermatomyositis, are visible without magnification.
Juvenile dermatomyositis, an inflammatory illness of unknown cause, primarily affects skin, muscle, and blood vessels. Affected children typically have characteristic skin lesions and muscle weakness. Characteristic dermatologic findings include periorbital and facial erythema often with edema; hyperkeratotic, red-to-pink papules over the knuckles of the hands, known as Gottron papules; and periungual telangiectasia, best seen with the aid of an ophthalmoscope or other form of magnification. The skin often demonstrates photosensitivity with the facial rash resembling a persistent sunburn. The butterfly pattern of the facial erythema may be mistaken for the malar blush of systemic lupus erythematosus.
Amyopathic dermatomyositis is characterized by typical cutaneous features of dermatomyositis in the absence of clinical or laboratory evidence of muscle disease. There is disagreement whether a diagnosis of dermatomyositis can be made without evidence of muscle involvement.1 Most cases of amyopathic dermatomyositis reported in the literature have been in adults. A review of published studies of patients with dermatomyositis reported that 2% to 11% of patients had this form of the disease.2 A review of 50 patients with dermatomyositis, aged 2 to 83 years at diagnosis, revealed that the onset of cutaneous lesions ranged from 51 months before to 14 months after muscle weakness onset.3 Skin involvement was the initial feature in 56% of these patients while only 16% presented with muscle weakness. Of additional interest, 12% of this group had had cutaneous lesions for longer than 1.75 years before the onset of muscle weakness, but eventually, all developed evidence of myositis.3
In another review of patients with dermatomyositis, 6 (11%) of 54 met the criteria for the diagnosis of the amyotrophic variety of the disease.1 The mean duration of skin disease without muscle involvement was 3.8 years (range, 2-8 years). Five of 6 patients were adults, and all were treated with high-dose steroids. None developed evidence of myositis. The single child in the series, aged 6 years, did not receive steroid therapy and developed evidence of myositis 3 years after the onset of skin disease.
In a prospective study of 13 patients with clinicopathologic features of dermatomyositis and normal muscle enzyme serum levels, 4 had no signs of myositis either clinically, by electromyography, or by muscle biopsy after 4 to 11 years of follow-up.4 Two patients in this series were children aged 7 and 14 years. Both developed clinical myositis, one 3 years and the other 6 months after the onset of cutaneous changes.
In a series of children presenting with characteristic cutaneous findings of dermatomyositis without initial symptoms of muscle disease for at least 6 months, all 5 developed myositis as evidenced by clinical weakness, elevations in serum muscle enzymes, and characteristic findings on electromyography and/or muscle biopsy in the subsequent 6 to 24 months.5 All of the children received an aggressive regimen of pulse, intravenous methylprednisolone therapy. None developed cutaneous calcifications, a complication reported in a much larger percentage of children who had rash preceding muscle involvement by more than 1 year (67% vs 27%).3
Although there have been occasional reports of adults who develop the characteristic cutaneous changes of dermatomyositis without manifesting evidence of myositis in subsequent follow-up examinations, reports of persistent amyopathic dermatomyositis in children are rare. Children with dermatomyositis without muscle involvement must be followed carefully for clinical and/or laboratory evidence of muscle involvement. Whether children without muscle involvement should be treated with aggressive therapy to prevent subsequent muscle involvement or calcinosis cutis remains to be determined.
Accepted for publication May 17, 1999.
Reprints: Asunción Vicente Villa, MD, Department of Dermatology, Hospital Sant Joan de Déu, Universidad de Barcelona, Pso/Sant Joan de Déu 2, 08950-Esplugues, Barcelona, Spain.
Picture of the Month. Arch Pediatr Adolesc Med. 2000;154(12):1264. doi: