Rheumatoid nodules are commonly talked about when rheumatoid arthritis (RA) is discussed. It might surprise you to know that only 7% of those newly diagnosed with RA have rheumatoid nodules. So they are not characteristic symptoms of newly diagnosed RA.
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Overtime, about 25% of those with positive Rheumatoid Factor (RF) develop nodules. Nodules are frequently present in the more severe cases of RA, those more likely to have rapid progression of joint destruction and to develop vasculitis. 75% of those with Felty’s syndrome, more common in white males, have rheumatoid nodules. Current smokers with RA plus nodules usually have more severe disease.
In those with seronegative rheumatoid arthritis, about 6% develop rheumatoid nodules.
The condition of having rheumatoid nodules is called rheumatoid nodulosis.
- The nodules form below the skin near joints.
- They are firm and frequently moveable.
- They are not tender and are not usually harmful.
- They are 2 mm (.008 inch) to 5 cm (2 inch) and may occur singly or in clusters.
- They are formed in three, under the microscope, stages:
- acute inflammation (not like the inflammation found in joints.)
- necrotic where the central tissue in the nodule dies. There is risk of infection and ulceration.
- Severity of the nodules is related to joint erosions and other severe features of RA. Genes play a role in the appearance of nodules.
Common sites for rheumatoid nodules are bony prominences
- hands, elbows, forearm, fingers
- hip prominences
- joints of feet
- back of head, heels, Achilles tendons, ears, penis, vulva
Those wheel chair bound or bed ridden may develop nodules over the low back and buttocks.
- lining of the lungs, the lungs
- lining of the heart
- lining of the abdomen
- vocal cords
About 8% of those receiving methotrexate treatment develop micro-nodules (<.5 cm). They are small, multiple and commonly seen around the finger joints. The reason is unknown. They are also associated with Imuran, Enbrel and Arava.
When the nodes are compressing a nerve or causing tissue damage because of their location, the nodules may be excised.