Dermatomyositis / Polymyositis

Dermatomyositis / Polymyositis is indexed under Musculoskeletal & Connective Tissue, Inflammatory Myopathies. Also known as DM, PM, inflammatory myopathies.

US prevalence

~5-20 per 100,000 Source: NIH NIAMS; Myositis Association. Cites federal and non-federal sources, and the record does not say which one gave this figure. Label: REPORTED.

ICD-10-CM codes

M33.1, M33.2

Typical onset

DM: bimodal (5-15 and 40-60); PM: >20

Course

managed

Body systems

musculoskeletal, dermatologic, pulmonary

Sex differences

F:M ~2:1

Racial and ethnic differences

Black Americans may have higher incidence

What this page does not establish

These figures describe populations, not individuals, and none of them is a diagnosis or a treatment recommendation. Prevalence estimates are approximate and reflect published ranges. Disparity figures are reported patterns, not causes.

Taxonomy last reviewed 2026-05-19. Each figure on the interactive page carries its own source and retrieval date, which can be later than this review.

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