Rheumatoid nodules are firm lumps that can form under the skin, a common manifestation of rheumatoid arthritis (RA). While associated with RA, not everyone with the condition develops them. They are generally benign, meaning they are not cancerous and typically pose no serious health threat.
Appearance and Common Locations
Nodules vary in size, from a pea to a golf ball. They feel firm or rubbery, and can be fixed or slightly movable under the skin. Their color usually matches the surrounding skin, though they may sometimes appear reddish or yellowish.
Most frequent sites are areas subjected to repeated pressure or trauma, particularly over bony prominences. Common locations include the elbows, fingers, knuckles, heels, Achilles tendon, or the back of the scalp.
Less commonly, nodules may develop in internal organs like the lungs, heart, or vocal cords. Internal nodules are often asymptomatic and discovered incidentally. However, their presence can indicate more severe or long-standing rheumatoid arthritis.
How Nodules Develop
Rheumatoid nodule formation links to chronic inflammatory processes in rheumatoid arthritis. Nodules represent granulomatous inflammation, where immune cells aggregate due to persistent inflammation. This involves inflammation of small blood vessels, known as microvasculitis, within affected tissue.
After the initial inflammatory response, immune cells and fibrous tissue deposit. This accumulation organizes into the distinct, firm nodule structure. The nodule’s central area often contains dead cells and debris, surrounded by a palisading layer of immune cells.
Factors associated with increased risk of developing rheumatoid nodules include seropositive RA, where individuals have detectable rheumatoid factor or anti-citrullinated protein antibodies (ACPA) in their blood. Severe RA and a history of smoking are also risk factors.
When Nodules Become a Concern
While often harmless, rheumatoid nodules can lead to complications requiring medical attention. If on a pressure point like an elbow or heel, they can become painful or tender, especially with everyday activities. Persistent pressure can also cause overlying skin to break down or ulcerate.
An open ulcer over a nodule creates an entry point for bacteria, increasing infection risk. Large or strategically located nodules can interfere with joint movement, limiting range of motion or causing discomfort. Cosmetic concerns may also arise, particularly if nodules are large or prominently visible.
Internal nodules rarely cause symptoms, though lung nodules might lead to breathing difficulties. Rapid growth, new pain, infection signs like redness or warmth, or any impact on function are reasons to consult a healthcare professional.
Managing Rheumatoid Nodules
If asymptomatic and causing no functional or cosmetic issues, no specific treatment is necessary for rheumatoid nodules. The primary approach involves controlling underlying rheumatoid arthritis, typically with disease-modifying antirheumatic drugs (DMARDs). DMARDs can help prevent new nodules and may reduce existing ones.
For symptomatic nodules, several interventions exist. Corticosteroid injections directly into the nodule may reduce inflammation and pain, offering temporary relief. If a nodule is large, painful, or frequently infected, surgical removal might be an option. However, nodules can recur even after excision.
Protecting pressure points where nodules are located can prevent complications like skin breakdown. This might involve padding or adjusting daily habits to reduce direct pressure. These strategies aim to alleviate discomfort and prevent further issues without removing the nodule itself.