Purpose of review: Childhood myositis (juvenile idiopathic inflammatory myopathies – JIIMs) is a rare, but important, group of rheumatic diseases. There has been continuing worldwide progress in the understanding of these diseases, and continuing pursuit of better therapies. We review some important contributions from the recent published literature.
Recent findings: Environmental triggers are present in the majority of children with myositis. Cancer is almost never a cause. Newer findings implicate a host of immunologic aberrations, perhaps driven by type I interferons, in addition to the humoral immunity long associated with juvenile dermatomyositis (JDM). Myositis-specific antibodies, once thought to be rare in JIIM, are now found in a significant minority because of the characterization of new antibodies. Although mortality is low, recent studies highlight the accumulation of tissue damage that occurs in JDM. Biologic therapies have an unclear place in the treatment of JIIM, but new protocols are being studied and may lead to better outcomes. Physical exercise, once controversial, likely has a role to play in treatment.
Summary: International work is continuing to expand our knowledge of the JIIM.