What are RA nodules?

RA nodules are one of the most common manifestations of RA that occurs outside of the joints. Features of the disease that occur outside of the joints are sometimes referred to as extra-articular. RA nodules can be associated with severe RA. Nodules develop under the skin (subcutaneously), typically in areas including the elbows, finger joints, wrist, hip, lower back, and Achilles tendon. However, they can occur internally in the tissue of the heart and lung as well. RA nodules are found in about 7% of patients at the time of initial diagnosis and affect about 30% of patients at some point during the disease.1

We are not certain why RA nodules develop. However, they are more common at pressure points in the body and may begin with trauma that occurs locally. They are usually painless and are thought to form in response to inflammation and are associated with the action of immune cells called helper T cells.1,2

 

Who is at risk for RA nodules?

Nodules mainly affect patients who have active disease, as reflected by an elevated level of rheumatoid factor (RF). In fact, about 40% of RA patients who are RF-positive also have nodules. They can occur in patients with less active disease. However, they are less common in this group. There is some evidence that smoking increases the risk for development of RA nodules, as well as other extra-articular manifestations of RA. Patients who have nodules early in the course of RA are at higher risk for developing more serious extra-articular manifestations later in the course of the disease.1

Will an RA nodule disappear?

Nodules may persist and enlarge, or they may shrink and disappear. They may also recur after disappearing for a period of time. It is difficult to predict how an individual RA nodule will behave.2

 

How can RA nodules be treated?

Most nodules pose only a cosmetic problem and, therefore, direct treatment is not necessary. RA nodules, as well as other extra-articular manifestations of the disease, will typically respond to conventional RA treatment, including disease-modifying anti-rheumatic drugs (DMARDS) that control inflammation. In the case of nodules that are subject to repeated trauma due to their location, affect normal motion, or are associated with deformity, surgical treatment (removal) may be used. Nodules should not be drained or injected due to the risk for infection. If a nodule becomes infected it must be removed and drained and the infection treated.2

 

Nodules associated with methotrexate treatment

Nodules can form as a complication of treatment with the DMARD methotrexate (MTX) or other drugs. This condition is sometimes referred to as accelerated rheumatoid nodulosis or ARN. ARN manifests as small nodules that form on the hands, feet, and ears of patients with RA who are receiving MTX treatment. In one study of MTX, 8% of RA patients who received MTX developed ARN. Nodules often shrink and disappear when MTX is discontinued. Other drugs associated with ARN include the immunosuppressive drugs azathioprine (Imuran), the DMARD leflunomide (Arava), and the TNF-inhibitor etanercept (Enbrel).2

Written by: Jonathan Simmons | Last reviewed: September 2013.
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