Osteoarthritis (OA) and rheumatoid arthritis (RA) are two distinct types of arthritis that affect the joints. RA is an inflammatory disease caused by an autoimmune reaction, while OA is a degenerative condition caused by the breakdown of cartilage from age or heavy use. Between 30 percent to 50 percent of adults over the age of 65 have osteoarthritis. Osteoarthritis is the most common form of arthritis.

You may be asking, “How do I know if I have osteoarthritis or rheumatoid arthritis?” Here’s what you need to know about OA versus RA symptoms and more. It’s also important to work with a healthcare provider to get an accurate diagnosis.

Symptoms

Both OA and RA can lead to pain, stiffness, and a decrease in mobility in the joints. But these symptoms show up differently for each condition.

Location of Symptoms

In rheumatoid arthritis, joint stiffness and arthritis pain are symmetrical, occurring on both sides of the body. In addition to pain and morning stiffness, RA often causes affected joints to swell and feel warm.

Unlike RA, osteoarthritis in the joints isn’t necessarily symmetrical since it’s based on wear and tear. In other words, one hand or wrist may be impacted, but not the other.

OA and RA may also affect different joints. OA tends to show up in the neck, hands, lower back, hips, or knees. RA usually appears first in the small joints in your hands and feet. Later, it may affect more joints, like those in your ankles, wrists, and knees.

It can be difficult to differentiate between OA and RA. The way the pain feels and the results of blood tests and imaging can help establish the right diagnosis.

Duration of Symptoms

Rheumatoid arthritis and osteoarthritis morning stiffness are different too. A general rule is that if your joints stay stiff in the morning for longer than 30 minutes, it’s more likely to be RA. If you are stiff for less than 30 minutes, it’s more likely to be OA.

Type of Pain

There are two types of pain: inflammatory and mechanical. People with RA present inflammatory joint pain that’s worse when at rest but can decrease in intensity with movement. On the other hand, mechanical pain gets worse with movement and improves at rest.

Type of Disease

Rheumatoid arthritis is a systemic disease that can cause general symptoms, such as fatigue and fever. RA can also cause inflammation in other parts of the body, including the eyes and the membrane that surrounds the heart. RA raises your risk for other health conditions like lung disease and cardiovascular disease.

Osteoarthritis is not a systemic disease and affects only the joints.

Causes

Rheumatoid arthritis is an autoimmune disease in which the immune system mistakenly attacks the joints in the same way that the immune system would normally fight viruses or bacteria. The joint damage in this type of arthritis is caused by the body’s immune system, resulting in inflammation that leads to pain, swelling, discoloration, and warmth, as well as progressive damage.

Osteoarthritis isn’t caused by inflammation. With heavy usage or aging, cartilage breaks down and exposes the bones of the joints. This results in pain, stiffness, and a decrease in mobility.

Risk Factors

Risk factors increase a person’s chance of developing a health condition. Your healthcare provider might ask about these when determining whether you have osteoarthritis or rheumatoid arthritis.

According to the Cleveland Clinic, risk factors for RA include:

• Having certain genetic changes (like those in the human leukocyte antigen genes, which help your body tell the difference between invaders and your tissue)
• Being exposed to pollution or other things that irritate the immune system
• Having a family history of RA
• Smoking
• Being female
• Being diagnosed with obesity

According to the Mayo Clinic, risk factors for OA include:

• Being female
• Having a history of joint injuries, even if they were many years ago
• Having a family history of OA
• Being diagnosed with obesity
• Having bone deformities, like cartilage that doesn’t work right or joints that didn’t form correctly
• Being older
• Putting stress on your joints repeatedly, even if you never experience a joint injury
• Having certain metabolic diseases, including diabetes

While there’s some overlap between these risk factors, a healthcare provider will take note of the relevant risk factors when making a diagnosis.

Diagnostic Process

Rheumatoid arthritis is generally diagnosed through a combination of a physical examination, blood tests, and imaging scans. The evaluation is usually performed by a rheumatologist.

Osteoarthritis is also diagnosed with a physical examination and may be followed up with imaging scans, such as an X-ray or an ultrasound. While there are currently no blood tests that can identify whether you have osteoarthritis, a joint fluid analysis may be performed to rule out other causes for joint pain, such as gout.

Imaging Test Results

While OA and RA have some overlap in how they show up on imaging tests, such as X-rays, MRI scans, or ultrasounds, what doctors see can also help them determine your diagnosis.

In joints affected by rheumatoid arthritis, imaging tests will show eroded bone and cartilage, narrower spaces between the bones that make up your joints, and even loss of bone around your joints.

With osteoarthritis, tests will show less space between the bones in your joint, bone spurs, cysts, parts of your bones that are filled with fluid, and thicker bone under what cartilage is left in the joints.

Disease Onset

Osteoarthritis and rheumatoid arthritis tend to begin at different times and progress at different paces.

OA tends to come on slowly. Because it develops as the cartilage between your bones deteriorates, it can slowly develop over months or even years.

RA, on the other hand, tends to develop and get worse much faster. It usually develops in a matter of a few weeks or maybe a few months. If you’ve wondered, “How quickly can rheumatoid arthritis spread?” the answer is that it can do so quite fast.

The age of onset for these conditions is also different. Osteoarthritis tends to be diagnosed after age 50, when cartilage has had time to wear down. Rheumatoid arthritis, on the other hand, tends to be diagnosed between the ages of 30 and 60, though it may appear as early as 16.

Disease Progression and Prognosis

As rheumatoid arthritis progresses, it can damage your bones and your joints. This can lead to joints that are deformed and very painful. Getting an accurate diagnosis early can help you get the treatment you need to avoid these kinds of complications. Because it can also show up in other parts of your body, you may experience other complications from RA as well.

Since osteoarthritis is limited to the joints, any damage you see will focus on those areas. While it can continue to cause joint damage over time, you won’t experience symptoms in other parts of your body.

Treatment

Rheumatoid arthritis treatment options usually target the immune system to calm inflammation, reduce autoimmune attacks on the joints, and ease symptoms. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, naproxen, and aspirin, may be used to relieve mild to moderate pain and inflammation in both forms of arthritis.

However, the mainstays of RA treatment are disease-modifying antirheumatic drugs, or DMARDs. DMARDs target the immune system to control the processes that cause inflammation and joint damage.

To relieve swelling and pain, corticosteroids can be used as bridge therapy until DMARDs start their action. In cases where DMARDs aren’t efficient, biologic therapy, which is proven to stop disease progression, can be used. In severe cases, surgery may be needed to repair or replace joints.

With osteoarthritis, symptoms can be managed with over-the-counter and prescribed treatments, including NSAIDs. Heating and icing joints can provide pain relief. Cortisone or hyaluronic acid injections may improve symptoms too. Surgery may be recommended in some cases. DMARDs wouldn’t help in cases of osteoarthritis, since OA isn’t an autoimmune disease.

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