Osteomyelitis (CRMO): Symptoms, Inflammation in Bones & Treatment
Chronic Recurrent Multifocal Osteomyelitis (CRMO) is a rare inflammatory bone disorder that mainly affects children and adolescents. It causes repeated episodes of pain, swelling and inflammation in different bones throughout the body. Although the term “osteomyelitis” usually refers to a bone infection, CRMO is not caused by bacteria, viruses or any other infection. Instead, it is considered an autoinflammatory condition, meaning the immune system becomes overactive and mistakenly causes inflammation in the bones.
CRMO most often develops in school-aged children and teenagers, with girls being affected more frequently than boys. The condition may involve one bone at first and later appear in other areas, which is why it is described as “multifocal.” The symptoms can come and go over time, with periods of improvement followed by flare-ups.
CRMO Symptoms
The symptoms of CRMO vary from person to person. Some children may have mild discomfort, while others experience more severe pain that affects daily activities.
Common CRMO symptoms include:
- Bone pain that may worsen at night or during physical activity
- Swelling, warmth or tenderness over the affected bone
- Limping or reduced ability to move comfortably
- Stiffness in nearby joints
- Fatigue or low energy
- Mild fever in some cases
- Symptoms that recur in different areas over time
CRMO commonly affects the long bones of the legs, pelvis, spine, collarbone, ankles, feet or ribs. In some children, pain may shift from one area of the body to another over several months or years.
Because symptoms may come and go, it can sometimes take a long time before the condition is correctly diagnosed. Some children are initially treated for sports injuries, growing pains or infections before CRMO is considered.
Causes and risk factors
The exact cause of CRMO is still unknown. Researchers believe it develops because of an abnormal immune response that triggers inflammation in the bones without any infection being present.
Several factors may play a role, including:
- Genetic factors
- Family history of inflammatory diseases
- Overactivity of the immune system
- Association with other inflammatory conditions
CRMO may occur alongside conditions such as psoriasis, inflammatory bowel disease, juvenile arthritis or severe acne. Having one of these conditions does not necessarily mean a child will develop CRMO, but doctors may look for these associated diseases during assessment.
Importantly, CRMO is not contagious and cannot spread from one person to another.
Diagnosis
Diagnosing CRMO can be difficult because its symptoms can resemble other conditions such as bone infections, fractures or even bone tumours. There is no single test that confirms CRMO, so doctors usually use a combination of medical history, physical examination, blood tests and imaging studies.
The diagnostic process may include:
- A detailed review of CRMO symptoms and medical history
- Physical examination to identify painful or swollen areas
- Blood tests to check for signs of inflammation
- X-rays to look for changes in the bones
- MRI scans to identify inflammation and detect multiple bone lesions
- Bone scans in some cases
- Bone biopsy if doctors need to rule out infection, cancer or other serious conditions
MRI is often the most useful imaging test because it can detect inflammation in several bones at the same time, even in areas that are not yet painful.
Chronic Recurrent Multifocal Osteomyelitis Treatment options
There is no single cure for CRMO, but treatment can help reduce inflammation, relieve pain and prevent complications. The choice of treatment depends on how severe the condition is, and which bones are affected.
Common treatment options include:
- Nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce pain and inflammation
- Corticosteroids for short-term control of severe flare-ups
- Disease-modifying antirheumatic drugs (DMARDs)
- Biologic medications for children with more severe or resistant disease
- Physical therapy to improve strength, flexibility and mobility
- Regular monitoring to assess bone health and growth
Many children respond well to NSAIDs alone, while others may need stronger medications if symptoms continue or if important areas such as the spine are involved.
Physical therapy can also play an important role by helping children stay active and maintain normal movement patterns.
When to see a doctor
Parents should seek medical advice if a child has:
- Persistent or recurring bone pain
- Swelling over a bone without an obvious injury
- Limping or difficulty walking
- Pain that wakes them up at night
- Symptoms that improve and then return
- Ongoing fatigue or reduced physical activity
Early diagnosis is important because it can prevent unnecessary treatments such as repeated antibiotics or surgery and can help protect the bones from long-term damage.
FAQs
Is CRMO curable?
There is no definitive cure, but many children improve significantly with treatment. Some may eventually go into remission and remain symptom-free for long periods.
Is CRMO an infection?
No. Despite its name, CRMO is not caused by bacteria or any other infection.
Can CRMO affect growth?
In some cases, if inflammation occurs near growth plates, it may affect bone growth. This is why regular follow-up is important.
Takeaway
CRMO is a rare but manageable inflammatory bone condition that mainly affects children and adolescents. Because it is not an infection, recognising it early can help avoid unnecessary antibiotics and delays in treatment. With the right care, many children are able to manage their symptoms, remain active and enjoy a good quality of life.