Chronic recurrent multifocal osteomyelitis (CRMO) is a rare nonbacterial cause of osteomyelitis. It is an autoimmune inflammatory disorder that causes multi-site, relapsing bone inflammation in the absence of typical infectious causes. Patients present with bone pain, swelling, and decreased mobility. CRMO most often occurs in children. CRMO sometimes co-exists with other autoimmune diseases such as inflammatory bowel disease or within a genetic syndrome. Nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroids, and bisphosphonates have all been used to treat CRMO. The disease typically has a relapsing and remitting course.

CRMO is now viewed by many as part of the spectrum of SAPHO syndrome.