Most studies reporting the incidence of idiopathic inflammatory myopathies (IIM) combine dermatomyositis (DM) and polymyositis (PM) and do not include patients with clinically amyopathic DM. In the US, the annual incidence of adult IIM is 5.5 to 8.9 cases per million. There is a trend towards increasing incidence over time, but this is likely to reflect improved diagnosis and reporting rather than a true increase in disease incidence. In Spain, the annual incidence of dermatomyositis has been determined at 4.9 per million.
BMJ Best Practice is an evidence-based point of care tool for healthcare practitioners.
To continue reading and access all of BMJ Best Practice's pages you'll need to log in or start a free trial.
You can access through your institution if your hospital, university, trust or other institution provides access to BMJ Best Practice through either OpenAthens or Shibboleth.
Use of this content is subject to our disclaimer