Osteoarthritis vs. Rheumatoid Arthritis: What’s the Difference?

“Arthritis” is a term you’ve probably heard before. But what does it mean? Arthritis refers to a disease that causes joint pain. “Arthro” means joint, and “itis” means inflammation. But there are different types of arthritis. Rheumatoid arthritis (RA) and osteoarthritis (OA) are two common types.

RA and OA both cause pain and swelling in the joints. But they are two very different diseases. It’s important to know the difference because they have different complications and treatments. And proper treatment can slow down joint damage from arthritis. 

What is rheumatoid arthritis?

Rheumatoid arthritis (RA) is an inflammatory condition that affects joints and other organ systems. It’s an autoimmune disease. This means your own immune system causes the problem. It results in inflammation in the joints, which causes pain, swelling, and stiffness. Over time, this can damage the joints. 

Promotional Disclosureinfo_outlined

SPECIAL OFFER

An interchangeable biosimilar to Humira® for 92% less

Introducing Adalimumab-adbm, an autoimmune medication that is the first-ever FDA-approved interchangeable biosimilar to Humira®. Get it for 92% less than the Humira® list price.

Save now

RA most commonly affects these joints: 

• Fingers

• Hands

• Wrists

• Feet

But it can affect other areas of the body, too. Beyond joint pain, RA might start with fever, fatigue, achiness, and loss of appetite. Over time, it can affect the: 

• Heart

• Lungs

• Skin

• Nerves

• Kidneys

• Blood vessels

• Bone marrow 

RA can affect anyone. Symptoms usually start around middle age — after age 30 in female adults and after age 45 in male adults. 

What is osteoarthritis?

Osteoarthritis (OA) is the most common type of arthritis. It’s estimated to affect over 30 million Americans. Like RA, OA also damages the joints, causing pain and swelling. But the cause of OA is degeneration (breakdown) of cartilage in the joints — not autoimmune disease. This happens over time with age. This is why people often describe it as the “wear and tear” of the joints. Symptoms typically appear after age 50. 

But OA can also happen earlier in life. For example, a joint injury or overuse (repetitive motion) can speed up the damage. Inflammation is also possible when OA “flares” or gets worse from time to time. But the inflammation is not the cause of the damage — it’s from degeneration. This can also lead to further joint breakdown.

Symptoms of OA can include:

• Joint pain that worsens with activity

• Joint stiffness and swelling

• Noisy joint movement (clicking or popping)

• Decreased joint movement due to pain or joint damage

OA can affect any joint in the body. But it’s more common in these areas:

• Hands

• Hips

• Knees

• Lower back

• Neck

What are the symptoms of OA vs. RA?

Similarities

Although OA and RA are very different conditions, they have some things in common. OA and RA are similar in that they:

• Cause joint pain, swelling, and stiffness

• Often affect the hands

• Are more common in people with female anatomy

• Can run in families

• Can cause symptoms in older adults 

Differences 

There are some key differences between OA and RA that can help your provider figure out the cause of your joint pain. This table highlights the key differences.Differences 

How do you know if you have OA or RA?

If you have joint pain, the best thing to do is to see your healthcare provider. They can help you figure out what’s going on. It’s helpful to know about any medical problems you or your family have because autoimmune diseases tend to run in the family. 

A physical exam is also important. Your provider will examine your joints for warmth, redness, and swelling. They will also see if you have symptoms on both sides of your body. Your exam will likely include bloodwork. There are several labs that can be abnormal in RA but not in OA. 

X-rays are also helpful in making the diagnosis. They can help your provider have a closer look at what’s happening in the joints. 

Can an X-ray show the difference between OA and RA?

Yes. Joints in RA look different than joints in OA. That’s why X-rays are a helpful tool for figuring out the cause of joint pain. On an X-ray, there’s less space between the bones in OA. But in RA,  the bone is more eroded. That said, X-rays can be normal in either condition if it’s caught early. 

Other imaging tests, such as MRI, can also be helpful. MRIs can offer more in-depth images of the joints. This can be especially helpful in the early stages of RA. An MRI can show joint inflammation even when X-rays are normal. So your provider may suggest an MRI if you have symptoms of RA but no evidence of arthritis on X-ray.  

Can any other tests show the difference between OA and RA?

Yes. Depending on what your exam and X-rays show, your provider might order blood tests, too. Since RA is an inflammatory, autoimmune disease, there are certain things to look for in the blood. These include markers of inflammation and autoantibodies.

Your healthcare provider will likely check these labs:

• Autoantibodies (like rheumatoid factor and anti-cyclic citrullinated peptide antibody)

• Complete blood count (CBC)

• Erythrocyte sedimentation rate (ESR)

• C-reactive protein (CRP) 

And if you have swelling in a large joint (like the knee), your provider might need to remove some fluid for testing. This can also give clues to whether it’s RA or OA.

What increases your risk for OA vs. RA?

There are several things that can increase your risk for developing OA. These include:

• Being over 50 years old

• Overusing a joint or having an injury

• Having a family history of OA

• Being born with female anatomy

• Having a heavier body weight

• Lacking of exercise and conditioning

Similarly, there are factors that may increase your risk of RA. These are:

• Being over 60 years old

• Having a family history of RA

• Having a genetic trait 

• Smoking

• Being born with female anatomy

• Having a heavier body weight

Can you have osteoarthritis and rheumatoid arthritis at the same time?

Yes. It’s possible to have both OA and RA at the same time. In fact, having RA also makes you more likely to develop OA. That’s because the chronic inflammation caused by RA can lead to repeated joint trauma. This increases the risk of OA over time. 

OA and RA may cause changes in the same joint, or they may affect different joints at one time. Keeping inflammation down and decreasing risk factors may help people with RA prevent OA.

Why trust our experts?

Written by:

Mandy Armitage, MD

Mandy Armitage, MD, has combined her interests in clinical medicine with her passion for education and content development for many years. She served as medical director for the health technology companies HealthLoop (now Get Well) and Doximity.

Edited by:

Karla Robinson, MD

Karla Robinson, MD, is a medical editor for GoodRx. She is a licensed, board-certified family physician with almost 20 years of experience in health through varied clinical, administrative, and educational roles.

Our editorial standards

Meet our experts