What Are Rheumatoid Nodules?
Some symptoms of rheumatoid arthritis (RA) occur outside of the joints. These are sometimes called extra-articular features. Rheumatoid nodules are a common symptom of RA that occurs outside of the joints.1
What are rheumatoid nodules?
Rheumatoid nodules are firm lumps that develop under the skin. They can range in size from the size of a pea to the size of a lemon. Nodules can develop in many areas, including:1,2
- Finger joints
- Lower back
- Achilles tendon
Nodules can also occur internally in the heart or lungs.1,2
About 7 percent of people with RA have nodules at the time of diagnosis. However, nodules affect 30 to 40 percent of people with RA at some point during the disease. Rheumatoid nodules can be linked to severe RA.1
Doctors are not certain why rheumatoid nodules develop. However, nodules are more common at pressure points in the body and may begin with trauma (injury) that occurs locally (at the site). They may form in response to inflammation. They are also linked to the actions of immune cells called helper T cells.1
Who is at risk for rheumatoid nodules?
Nodules mainly affect people who have high levels of rheumatoid factor (RF). Rheumatoid factors are proteins made by the immune system. Rheumatoid factors can mistake healthy cells for harmful ones, attacking healthy tissue and cells in the body. About 40 percent of people with RA who are RF-positive (also known as seropositive) have nodules. Nodules can also occur in people with less active disease, but this happens less often.3
It is possible that smoking increases the risk of developing rheumatoid nodules and other symptoms outside of the joints. People with nodules are more likely to develop more serious symptoms outside of the joints later in the course of the disease.1
Most nodules do not cause problems, and direct treatment is not usually needed. Rheumatoid nodules will usually respond to normal RA drugs. In some cases, nodules can be painful, damage the skin, or be in a problematic location and require treatment.3
For some serious cases, the nodules may affect your range of motion. They can also sometimes stick out in a spot that may damage the nodule if it is repeatedly hit. For example, a nodule on the bottom of your foot could be easily damaged. In these cases, your doctor may recommend surgical treatment. Unfortunately, nodules sometimes grow back at the same place they were removed.2
Injecting nodules with steroids may make them smaller, but this increases the risk for infection. If a nodule becomes infected, it must be removed and drained. The infection will then need to be treated.2
Can they disappear on their own?
Nodules may stick around and grow, or they may shrink and disappear. They may also come back after disappearing for some time. It is difficult to predict how rheumatoid nodules will behave.2
Links to methotrexate treatment
Nodules can sometimes form as a complication from treatment with methotrexate (MTX) or other drugs. Methotrexate is a common traditional disease-modifying antirheumatic drug (DMARD). This drug was first used as a cancer-fighting drug but is now a first-line treatment for RA.2,5
In a few cases, methotrexate can cause small nodules on the hands, feet, and ears. If the nodules become problematic, your doctor may recommend you switch to a different RA drug. Stopping methotrexate usually causes the nodules to shrink and disappear.2,5
Other drugs may cause nodules, including ImuranⓇ (azathioprine), AravaⓇ (leflunomide), and EnbrelⓇ (etanercept).2,5