Chronic recurrent multifocal osteomyelitis




Chronic recurrent multifocal osteomyelitis (CRMO) ("multifocal" because it can erupt in different sites, primarily bones; "osteomyelitis" because it is very similar to that disease but appears to be without any infection), is a rare condition (1:1,000,000), in which the bones have lesions, inflammation, and pain. Its definition is evolving. Many doctors and articles described CRMO as an autoimmune disease that has symptoms similar to osteomyelitis, but without the infection. Some doctors thought CRMO was related to SAPHO syndrome. Cutting edge research now classifies CRMO as an inherited autoinflammatory disease but have yet to isolate the exact gene responsible for it. Some specialists believe they have discovered a link between CRMO with a rare allele of marker D18S60, resulting in a haplotype relative risk (HRR) of 18. Other experts found that "mutations in LPIN2 cause a syndromic form of chronic recurrent multifocal osteomyelitis known as Majeed syndrome, while mutations in pstpip2 cause a murine form of the disorder. The roles played by LPIN2 and the human homolog of pstpip2, PSTPIP2, in the etiology of chronic recurrent multifocal osteomyelitis are uncertain but are currently being investigated." The professional theories seem to be moving in the direction of an inherited gene.


  • Bone pain 
  • Bone inflammation 
  • Bone lesions 
  • Bone swelling 
  • Skin redness


No one knows what causes CRMO. Some possible causes include infectious disease, autoimmune reaction (where the body’s immune system attacks the normal cells itself) or a problem in the immune system.


An MRI or bone scan can reveal the inflammation and/or lesions of CRMO. However, laboratory tests may also help in discovering inflammation by checking C-reactive protein level, erythrocyte sedimentation rate, level of peripheral leukocytes, ferritin level, anti-nuclear antibodies level, and rheumatoid factor status.


A doctor could easily misdiagnose CRMO as muscle spasms or simple inflammation and routinely prescribe antiinflammatory medicines, which is the normal treatment for CRMO. Many childhood aches and pains are dismissed as growing pains however the pain that causes CRMO is much more painful and complex than this. CRMO has deep, aching pain, swelling, and a possible fever but not always. A limp may be falsely considered as the result of an over-active lifestyle. A parent or doctor may not associate a longer limb with CRMO. Without an x-ray, MRI, or bone scan, the bone lesions will go undetected.

A diagnosis of CRMO is often made after a bone biopsy and MRI have ruled out other diseases that cause painful bone lesions/tumors such as bacterial osteomyelitis, ewing sarcoma, leukemia, lymphoma, rhabdomyosarcoma, neuroblastoma metastasis, eosinophilic granuloma, or Langerhans cell histiocytosis. When all the previous illnesses are ruled out and a bone biopsy turns up negative for any known cancer, bacteria, or fungus, CRMO is usually diagnosed.


Since CRMO is an autoinflammatory condition it can wax and wane. Flare ups are common with periods of remission in between. Flare ups are also more common during childhood growth spurts. The prognosis can vary among individuals: some children may go into complete remission when they become adults and some may continue with this disease.


CRMO patients suffer from inflammation and possibly intense pain. As such, the most common prescription is for anti-inflammatory such as NSAIDs and steroids. The goal is to rid (or reduce) the body of inflammation and that should ameliorate CRMO. Antibiotics are not commonly prescribed because there is no bacterial or fungal infection. But some doctors do prescribe the antibiotic azithromycin because, in addition to its antibacterial properties, azithromycin also has anti-inflammatory and immuno-modulatory properties.

Schilling and Wagner wrote an article that CRMO patients seem to improve greatly with azithromycin:

In one study, 7 out of 13 patients, mainly teenager, showed a fast clinical improvement after they were started on azithromycin. The immediate therapeutic effect of azithromycin in patients with CRMO was surprising and lead to the hypothesis that azithromycin could have an antiphlogistic in addition to its antibiotic effect in this disease setting.

A Malaysian clinic had a very different approach which seems to have worked:

She (9 yr old girl) underwent curettage through a small oval corticotomy window on the first metatarsal bone. The pain and swelling improved promptly and she was able to walk without pain 2 weeks later. Curettage enabled rapid symptomatic relief and induced remission, with little risk of complications.

Physical therapy has helped some CRMO patients. Physical therapy works to maintain and/or restore movement and flexibility.