Dermatomyositis with a pityriasis rubra pilaris-like eruption: an uncommon cutaneous manifestation in dermatomyositis.

A pityriasis rubra pilaris-like eruption has been described in patients with dermatomyositis. We describe an 11-year-old girl with dermatomyositis who had additional clinical findings of pityriasis rubra pilaris. Over a year, she developed muscle weakness, increasing fatigue, and a markedly elevated creatinine kinase level in addition to her cutaneous eruption and was seen in our clinic for these complaints. A year earlier, when a generalized, scaly erythematous eruption had appeared, she had been diagnosed as pityriasis rubra pilaris clinically and histopathologically. Dermatologic examination found scaling erythematous plaques involving the trunk and upper and lower extremities. Islands of unaffected skin were intermingled with erythematous plaques that were characteristic of pityriasis rubra pilaris. A skin biopsy specimen showed the findings of dermatomyositis and that diagnosis was made. The laboratory findings, electromyographic pattern, and muscle biopsy were also consistent with dermatomyositis. Her presentation is interesting, as she had been diagnosed as pityriasis rubra pilaris both clinically and histopathologically 1 year earlier and, although the cutaneous lesions had not changed, a diagnosis of dermatomyositis was made a year later.