Macrophage activation syndrome in the early phase of juvenile dermatomyositis: a case report.

Abstract

There are only few reports about macrophage activation syndrome (MAS) in the early phase of juvenile dermatomyositis (JDM). We describe an 8-year-old boy who was diagnosed as having JDM with the manifestation of MAS. He developed fever, blisters on his cheeks, and oral and lip aphtha. One month after from his first symptoms, his serum ferritin significantly elevated (2366ng/mL) without cytopenia. After a period of normal temperature of 2 weeks, remittent fever appeared to him again with skin rashes on his cheeks, femoral pain and leukopenia. There was no apparent muscle weakness but mild pressure pain at the posterior region of his thigh near the knees. Gadolinium-enhanced MRI of his thigh revealed fasciitis at the pressure pain region, and the skin pathology of the rash was consistent with JDM. We diagnosed him as having JDM with MAS caused by hypercytokinemia. Medications including methylprednisolone pulse therapy and oral methotrexate were administered, and since then he is stable without a relapse. MAS can develop not only in juvenile idiopathic arthritis but also in other juvenile rheumatic disorders. In this case, as the skin manifestation and muscle weakness was slight, skin pathology and gadolinium-enhanced MRI was useful for the diagnosis.