RA can cause solid, round lumps called rheumatoid nodules to develop in the body. Rheumatoid nodules typically form below the skin at pressure points near joints, particularly the fingers, elbows, and feet.
- May be smaller than a pea or as large as a walnut, or even a lemon
- Feel hard or rubbery, not squishy
- May move around under the skin or be fixed in place, attached to soft tissues
- Typically do not hurt when the skin over them is pressed
About 35% of people with RA develop rheumatoid nodules at some point. About 7% have nodules at the time of diagnosis.1
There are two types of rheumatoid nodules:
- Subcutaneous rheumatoid nodules (sub means under, and cutaneous means skin) develop just under the skin. The vast majority of rheumatoid nodules are subcutaneous, and most do not require biopsy or treatment.
- Noncutaneous rheumatoid nodules cannot be seen or felt just under the skin. Instead, these nodules can form in places like the lungs, heart, spine, and areas around the eyes and inner ears. These nodules are sometimes called systemic rheumatoid nodules, and they account for less than 1% of rheumatoid nodules.
Noncutaneous nodules can cause problems in areas other than the lungs. For example, nodules near the heart can raise the risk of stroke, and nodules in the ear can contribute to hearing loss.4
Experts are not sure exactly why rheumatoid nodules develop. They seem to be more likely to develop when RA is undiagnosed, severe, or not well managed.
Factors that raise the risk of developing rheumatoid nodules include5:
- The presence of proteins called rheumatoid factor in the blood (detected with a lab test)
- Taking certain drugs that reduce other RA symptoms, such as methotrexate and anti-TNF inhibitors
- The presence of gene HLA-DRB1
Most rheumatoid nodules are not a problem and do not require treatment. Treatment may be recommended if a nodule:
- Breaks through the skin
- Becomes infected
- Interferes with joint function
- Impinges on nerve tissue
- Causes pain or poses another specific risk or problem
There is no surefire way to reduce or eliminate rheumatoid nodules. Suggested treatment options include corticosteroid injections and stopping or changing medications. While not common, surgery to remove a nodule may be recommended.5