Rheumatoid arthritis (RA) nodules are the most common sign of RA after joint symptoms. RA is an autoimmune disease, which means that your immune system—your body’s defense system—mistakenly attacks normal cells of your body, causing inflammation. With RA, most of the inflammation takes place in the lining inside your joints, called the synovium. However, RA inflammation can also cause firm lumps, or nodules, under your skin. Most of the time, nodules form after joint symptoms have already developed. You may never get nodules. In fact, just 25% of people with RA do. If you're taking the RA drug methotrexate, your chances of getting nodules are higher. There's some evidence that newer medications for RA, called disease-modifying anti-rheumatic drugs (DMARDs), are decreasing the risk for nodules. Signs and Symptoms of RA Nodules You can have single or multiple nodules. They usually feel firm and painless, and you might be able to move them around under your skin. The skin over the nodules usually does not change color, but you may notice that it looks shiny. RA nodules usually form over pressure points and parts of your body that get wear and tear, so you're more likely to get them around your elbows, hands, and heels. You may also notice these signs and symptoms: RA nodules related to methotrexate tend to be smaller and appear mainly in fingers and elbows. Most RA nodules range from pea size to the size of a golf ball or lemon. RA nodules can be uncomfortable when they're large or located on areas that are sensitive, like the palms of your hand or soles of your feet. RA nodules can be painful if they are pushing on a nerve, or if they become infected. Diagnosing RA Nodules If you've already been diagnosed with RA, diagnosing RA nodules is easy. A physical exam is probably all you will need. If nodules show up before other RA symptoms, which they sometimes do, you may need a blood test to look for rheumatoid factor (RF). RF is an antibody that most people with RA make. Most people with RA are positive for RF, and almost all people with RA nodules are positive for RF. A biopsy, or a sample of cells, from a nodule is rarely necessary, but in some cases, you may need it. That's because other lumps and bumps can look and feel like RA nodules. When a doctor looks at a sample of an RA nodule under a microscope, it shows a specific type of inflammation. Treating RA Nodules You may not need treatment for RA nodules. However, if they're very unsightly, cause discomfort, limit your activity, or become infected, treatment may help. Your options include: Switching to another RA drug or adding another RA drug if your nodules are caused by methotrexate Getting a strong anti-inflammatory steroid medication injection (this has a risk for infection) Having surgery to remove nodules that are very uncomfortable or infected, although nodules do have a tendency to return Key Takeaways RA nodules are the most common sign of RA after joint symptoms. Nodules occur in up to 25% of people with RA, usually as a later sign of the disease. People most likely to develop nodules are those with a positive RF and those taking methotrexate. RA nodules are usually painless, but they can cause problems if they're large, uncomfortable, or infected. You may not need treatment for RA nodules, but in some cases, your doctor may recommend a change in your RA medication, steroid injections, or surgery.