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 Tilstra JS, Lienesch DW. Rheumatoid Nodules. Dermatol Clin. 2015;33(3):361-371. doi:10.1016/j.det.2015.03.004 PMID: 26143419
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 most often develop in the lungs. These nodules typically have no symptoms but may increase the risk for potentially life-threatening conditions, such as a collapsed lung. 2 Vantrease A, Trabue C, Atkinson J, McNabb P. Large endocardial rheumatoid nodules: a case report and review of the literature. J Community Hosp Intern Med Perspect. 2017;7(3):175-177. Published 2017 Jul 13. doi:10.1080/20009666.2017.1340731 PMCID: PMC5538220 , 3 Esposito AJ, Chu SG, Madan R, Doyle TJ, Dellaripa PF. Thoracic Manifestations of Rheumatoid Arthritis. Clin Chest Med. 2019;40(3):545-560. doi:10.1016/j.ccm.2019.05.003 PMCID: PMC6994971
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 Emamifar A, Bjoerndal K, Hansen IM. Is Hearing Impairment Associated with Rheumatoid Arthritis? A Review. Open Rheumatol J. 2016;10:26-32. Published 2016 Mar 15. doi:10.2174/1874312901610010026 PMCID: PMC4797675
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 include 5 Mehta, B. Clinical Epidemiology in Rheumatology. In: Efthimiou P, ed. Absolute Rheumatology Review. Electronic book. Springer; 2020: 37-49. Accessed May 12, 2021. https://doi.org/10.1007/978-3-030-23022-7 :
- 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 Mehta, B. Clinical Epidemiology in Rheumatology. In: Efthimiou P, ed. Absolute Rheumatology Review. Electronic book. Springer; 2020: 37-49. Accessed May 12, 2021. https://doi.org/10.1007/978-3-030-23022-7