Rheumatoid Nodules

What rheumatoid nodules are

Rheumatoid nodules form where small blood vessels become inflamed, leading to a core of dead tissue (fibrinoid necrosis) surrounded by a wall of immune cells arranged in a palisade. They often develop in areas exposed to repeated pressure or friction.

They range from pea-sized to walnut-sized or larger, and may be:

• firm and rubbery
• movable under the skin, or fixed to underlying tissue
• single or multiple
• usually painless unless pressed or inflamed

Who gets them

• people with rheumatoid arthritis, especially with positive rheumatoid factor or anti-CCP antibodies
• longer and more severe disease
• smokers
• men slightly more than women among people with RA
• rarely, people without RA (benign rheumatoid nodules in children, and with lupus)

Rheumatoid nodules are linked to a higher chance of other extra-articular RA features, such as lung disease and vasculitis.

Where they appear

Methotrexate-induced nodulosis

Some people develop many new small nodules, often on the fingers, after starting methotrexate, even while their joints improve. This accelerated nodulosis may improve if the medicine is changed, though doctors weigh this against good joint control.

Conditions that look similar

Diagnosis

Diagnosis is usually based on location and appearance in someone with RA. If uncertain, a doctor may:

• use ultrasound to tell a nodule from bursitis or a cyst
• aspirate to look for gout crystals
• biopsy the lump
• order chest imaging if lung nodules are suspected, since lung nodules in RA must be distinguished from cancer or infection

Treatment

Many nodules need no treatment. Options include:

• controlling RA with disease-modifying drugs and biologics, which can shrink nodules in some people. Rituximab has been reported to reduce nodules
• protecting pressure points with padding, cushioned seating and comfortable footwear
• steroid injection into a painful nodule
• surgical removal for nodules that are painful, infected, ulcerating, compressing a nerve or limiting function. They can recur
• stopping smoking
• reviewing methotrexate if nodulosis is troublesome

Outlook

Rheumatoid nodules are usually harmless. They may shrink, stay the same or grow over time, and sometimes disappear on their own. They are a marker of more active or severe RA, so their presence prompts attention to overall disease control.

Frequently asked questions

What are rheumatoid nodules?

They are firm lumps under the skin that develop in some people with rheumatoid arthritis, typically over pressure points such as the elbows, fingers and heels. They are made of inflamed tissue and are usually painless.

Are rheumatoid nodules dangerous?

Usually not. Most are harmless. Problems arise if they become infected, ulcerate, press on nerves or affect organs such as the lungs. They indicate more active RA, so good disease control matters.

Do rheumatoid nodules go away?

Some shrink or disappear on their own or with better RA control. Others persist for years. Surgically removed nodules can come back.

Can methotrexate cause rheumatoid nodules?

Yes. Some people develop many new small nodules after starting methotrexate, even as their joint symptoms improve. This is called accelerated nodulosis. Your rheumatologist can discuss whether a medicine change is worthwhile.

How are rheumatoid nodules treated?

Many need no treatment. Painful or problem nodules can be injected with steroids or surgically removed. Better control of rheumatoid arthritis and padding over pressure points also help.