What to Know About Pannus and Rheumatoid Arthritis

What It Is, Causes, Side Effects, Treatment, and More

Pannus is abnormal thickening of the synovium (joint lining), leading to growth at the joints, bones, and other tissues. Pannus can cause severe pain and swelling. It can cause damage to the bones, cartilage, and nearby tissues. 

The most common cause of pannus is rheumatoid arthritis (RA), a type of inflammatory arthritis that causes inflammation of the synovial linings of joints. But RA is not the only cause, and other inflammatory diseases might cause it.

Fortunately, advances in RA treatments, including biologics, have reduced this disease complication. If pannus does occur, it can be treated by managing its underlying cause—chronic, uncontrolled inflammation.

This article will cover everything you need to know about pannus, including how it forms, its causes, treatments, and more.

Rheumatoid Arthritis in the Knee

Why Pannus Forms

The synovium is the delicate membrane that lines the entire inner surfaces of joints except where the joint is lined with cartilage—the soft, resilient, and protective material at the ends of bones. The synovium has many functions, including lubricating the joints, supplying nutrients, and creating collagen (a natural fiber that connects tissues).

Synovial tissue can grow too much in people with rheumatoid arthritis. The extra synovial tissue thickens and grows into areas it generally would not.  

Certain immune system cells—mainly T-cell and B-cell lymphocytes—are to blame for the pannus formations. In RA, these cells are stimulated to produce cytokines—signaling proteins that trigger or increase inflammation. This increases blood flow to the synovium and results in thickening, which leads to pannus formation.

Pannus formations can grow in any synovial joint, but it mainly affects the wrists, the metacarpophalangeal joints connecting the palm of the hand to the fingers, the proximal interphalangeal joints (the middle joints of the fingers), and the cervical joints of the neck.

Pannus in the cervical joints of the neck can lead to severe complications, including misalignment of the cervical vertebrae (bones of the spine at the back of the neck). 

What Causes Pannus?

A primary cause of pannus is rheumatoid arthritis. It typically occurs if RA is untreated or your healthcare provider cannot find a treatment to manage it effectively. But this is rare, especially with the many aggressive treatment options available. 

Pannus can also affect people with ankylosing spondylitis (AS), a type of inflammatory arthritis that causes long-term inflammation of the small joints of the spine and the sacroiliac (SI) joints of the pelvis.

Like RA, AS can lead to pannus in the cervical spine, especially at the atlantoaxial joint. This is the joint at the upper part of the neck, containing the first and second cervical vertebrae.

Psoriatic arthritis (PsA), a type of inflammatory arthritis that affects the joints and skin, has been linked to pannus formation. Like RA, PsA causes synovitis (inflammation of the joint lining). Prolonged inflammation can lead to pannus formations that can damage joint cartilage.

Juvenile idiopathic arthritis (JIA), the most common arthritis affecting children, can also create pannus. It can cause cervical spine lesions and synovial inflammation, leading to pannus formation and bone marrow swelling. Pannus in JIA causes similar symptoms to RA-related pannus and can lead to the same type of bone, joint, and cartilage damage.

RA, AS, PsA, and JIA are all autoimmune diseases in which the immune system malfunctions and attacks healthy tissues throughout the body, especially the joints. Researchers don't know why this occurs, but they suspect certain genes make it more likely for someone to develop the condition.

But genes alone are not enough to cause these diseases. Factors in your environment, such as smoking (including secondhand smoking) and infections, can, in combination with genes, cause RA and or another autoimmune disease to occur.

Some research suggests that cervical pannus can occur in people who have used corticosteroids for a long time. Cervical pannus can also develop without RA, although some researchers think these people may have undiagnosed RA.

Symptoms and Diagnosis of Pannus

The symptoms of pannus are similar to those experienced in RA. This includes pain, swelling, stiffness, and tenderness of joints. All these symptoms are aggravated in the joint area affected by the pannus growth. Pannus formations can be quite painful and may lead to swelling that causes joints to appear distorted.

Pannus can cause excess synovial fluid production. When the pannus grows, it causes more synovial fluid to develop, leading to further inflammation, swelling, and tissue damage.

Cervical pannus can put pressure on any part of the cervical spine, especially at the craniocervical junction, the area between the skull and the cervical spine. It can lead to cervical instability and cause neck pain and stiffness, decreased neck motion, severe fatigue, problems with walking, increased clumsiness, and numbness and tingling in the arms.

During a physical exam, the swelling of the pannus-affected joint can be felt and seen. The affected joint area will feel spongy, soft, and warm. 

Once you are diagnosed with RA, it is crucial to start treating with a rheumatologist (a healthcare provider who diagnoses and treats diseases that affect the joints, muscles, and bones). You will need to see a rheumatologist several times a year so they can adequately manage and treat your disease. 

During routine visits, your rheumatologist will physically examine your joints. If pannus forms, it can be managed and treated before it causes any serious harm. You should let your healthcare provider know if you start to feel any growths below your skin at your joints. 

If your healthcare provider suspects pannus, they will request imaging to determine if joints are damaged or deformed. Imaging studies for RA might include X-rays, magnetic resonance imaging (MRI), and computed tomography (CT) scans.

These images can look for pannus formations and help your healthcare provider to determine if formations are large enough to damage bone, cartilage, or tissue.

Pannus Side Effects

Pannus formation in people with rheumatoid arthritis can damage joints, bones, and nearby tissues. Over time, this could mean severe pain, joint stiffness, and problems with mobility. 

A pannus growth might invade nearby bone or cartilage. These growths are sometimes aggressive and behave like tumors obstructing and putting pressure on nerves, bones, and other tissues. Bone mass might also be lost in a bone located at the pannus-affected joint. 

If there is further RA progression or nothing is done to treat the pannus, damage to the cartilage and bone erosion will occur. Pannus formation can also lead to bone marrow problems if pannus formation is in the bone marrow space.

How Is Pannus Treated?

RA inflammation results from an overactive immune system that mistakenly attacks healthy tissues leading to high levels of inflammation and, sometimes, pannus.

Currently, no medication or procedure can reverse the effects of pannus, but RA treatments can help manage symptoms, stop inflammation, and slow disease progression. With RA inflammation halted, pannus can also be prevented or slowed down. 

Preventing Joint Destruction

If you frequently have swelling and stiffness, you are more likely to experience RA joint damage. Fortunately, your healthcare provider can prescribe treatments to reduce inflammation and prevent joint damage. Various medications are available to manage the disease and prevent complications like joint damage and pannus. 

The American College of Rheumatology recommends treating RA with disease-modifying antirheumatic drugs (DMARDs). These drugs can effectively suppress an overactive immune system, which may reduce the development of pannus. They can also keep RA inflammation at the lowest possible levels in the body, and in some cases, they can lead to clinical remission (absence of RA signs and symptoms).

DMARD treatment categories include conventional DMARDs (cDMARDs), biologic DMARDs (bDMARDs), and targeted synthetic DMARDs (tsDMARDs). The most common drug treatments for RA are cDMARDs, which include Trexall (methotrexate) and Azulfidine (sulfasalazine).

Biologic DMARDs that treat RA include Humira (adalimumab), Remicade (infliximab), and Actemra (tocilizumab). TsDMARDs are a newer type of biologic for RA and include Xeljanz (tofacitinib) and Rinvoq (upadacitinib). 

Some research suggests interleukin 6 (IL-6)—a type of inflammatory protein—can stimulate pannus formation. That means it is possible for biologic DMARDs like Actemra can target IL-6 and halt pannus formation.

Nonsteroidal anti-inflammatory drugs (NSAIDs) may also help manage symptoms of RA. Medications, like Advil (ibuprofen) and Aleve (naproxen sodium), are available over the counter and can help to reduce inflammation, swelling, and joint stiffness. Your healthcare provider can also prescribe stronger NSAIDs to help manage more severe pain and swelling. 

Your healthcare provider may prescribe corticosteroids to decrease inflammation and pannus formation. Examples include prednisone and methylprednisolone.

Corticosteroids are only prescribed for short periods (less than three months) because long-term use can lead to serious side effects, such as osteoporosis (bone thinning), elevated eye pressure, high blood pressure, and swelling in the lower legs.

Physical therapy might help you to manage the day-to-day effects of RA. It has been found to reduce inflammation, pain, and disability through exercises designed to improve mobility and keep joints healthy. You may not need a physician referral to go to physical therapy, but it is a good idea to check your insurance guidelines to be certain.

In severe cases, your healthcare provider may recommend surgery to repair, remove, or fuse bones that RA and pannus have damaged. Surgery can reduce pain in the affected joint and prevent further damage. 

Surgery is considered a last resort option for RA. Your healthcare provider will only recommend surgery if your RA is severe, and you have exhausted all available options to halt disease progression.

Home Remedies

Medications can help manage RA, but medicinal treatments can be more effective when incorporated with home remedies. Home remedies can help slow disease progression, reduce inflammation that leads to problems like pannus, and manage symptoms like pain, swelling, and stiffness. These include:

  • Aquatic exercise: Aquatic exercise or hydrotherapy is helpful for people with RA. One 2017 study found that aquatic exercises improved disease activity in women with RA. Many study participants reported significant pain and improved functional capacity after only eight weeks of aquatic therapy.
  • Stay active: Other types of light to moderate activity (i.e., walking and running) can also help manage RA's effects, including inflammation that leads to pannus. Your healthcare provider or a physical therapist can help you develop a safe and effective plan for your fitness level. 
  • Rest: If you are experiencing high levels of inflammation, it is vital to rest painful, stiff joints. You will want to move and stretch joints but try to balance rest and activity.
  • Hot and cold therapies: Heat therapy can boost circulation to soothe stiff, achy muscle areas, and cold therapy can reduce swelling and numb pain.
  • Diet: Eat a healthy diet to decrease RA inflammation, especially with high inflammation levels. Try incorporating anti-inflammatory foods like fatty fish, berries, fruits, vegetables, nuts and seeds, and spices like turmeric. Research shows anti-inflammatory foods that contain omega-3s can help reduce inflammation in the body and may play a role in regulating the immune system. You will also want to avoid inflammation-promoting foods like high-salt foods, red and processed meats, refined carbohydrates, ultra-processed junk foods, and sugary beverages.
  • Quit smoking: Smokers have an increased risk for more severe RA, which includes complications like pannus. Smoking also decreases the effectiveness of RA drugs and can affect your ability to be physically active, which is extremely important with RA. If you are a smoker, it is never too late to quit. Talk to your healthcare provider about how to end the habit for good.

What's the Outlook for Someone With Pannus?

Most RA treatments can slow down pannus growth in the early stages of RA. Even if your RA is well-managed, you may still experience inflammation and joint pain, but joints are functional, and damage is slowed down. 

In people with long-standing RA where inflammation is not well-managed, pannus formations can grow and become a significant problem. This could mean more joint pain, swelling, and stiffness. Mobility might also be affected, and there might be permanent damage to the affected joint. 

Fortunately, treatment and outlook for people with RA have improved considerably in recent decades. Medications can manage symptoms and reduce or slow the formation of complications like pannus and RA disease progression. 

Summary 

Pannus is an abnormal growth or thickening in the joint linings. The most common cause of pannus is rheumatoid arthritis, which causes inflammation in the synovial linings of joints. Fortunately, this RA complication usually can be prevented by managing and treating RA. Other types of inflammatory arthritis cause synovial inflammation and might also lead to pannus.

Pannus can occur in people whose RA is not well-treated or who have severe disease. Left untreated, pannus can damage bones, joints, and nearby tissues. It can also affect joint function and mobility. 

Your treatment options for managing RA and effects like pannus include DMARDs, NSAIDs, corticosteroids, and physical therapy. You can also manage RA with various home remedies, including water-based activity and other exercises like walking and running, resting affected joints, eating healthy, and not smoking.

These therapies can reduce pain and other disease symptoms and slow disease progression. Surgery is considered in cases where RA and pannus have affected joint function or are causing significant pain. 

The outlook for people with RA who experience pannus can be good. This is because RA is a treatable condition, and you have many options for managing it and reducing its effects.

If you start feeling any growth just below your skin at your joints, or if you find your joints are frequently stiff and swollen, you should let your healthcare provider know. They check your joints, request imaging to determine the source of symptoms, and prescribe treatments to reduce further problems. 

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Lana Barhum

By Lana Barhum
Lana Barhum has been a freelance medical writer since 2009. She shares advice on living well with chronic disease.