Macrophage activation syndrome in juvenile dermatomyositis: a systematic review.

Macrophage activation syndrome (MAS) is a potentially fatal complication of a number of rheumatological conditions, but few studies assessed it in juvenile dermatomyositis (JDM). Indeed, MAS is not considered as a frequent complication of JDM, but its occurrence could be under-estimated. In order to address this issue, we performed a revision of the available medical literature, describing and assessing patients with both MAS and JDM. After retrieving 253 records initially, 11 papers were selected as appropriate for our research objective, which provided a total of 12 patients affected with both MAS and JDM. Our pooled case series suggested that MAS in JDM may not be very rare, even though no final conclusion about its incidence and mortality rate can be made. However, JDM-related MAS seems to be difficult to treat, since methylprednisolone pulse therapy alone was not sufficient in most cases. Moreover, MAS in JDM patients often occurred at the onset of the rheumatic disease, before the final diagnosis of JDM could be established. Finally, MAS criteria validated for systemic Juvenile Idiopathic Arthritis (sJIA) resulted to be a very useful guidance to diagnose MAS in JDM patients as well, but their reliability may not be absolute. Therefore, cohort and multicenter studies are needed to assess the incidence and improve the diagnostic criteria for MAS in JDM patients.