Both osteoarthritis (OA) and rheumatoid arthritis (RA) are different types of arthritis that affect the joints. Unlike RA, osteoarthritis is not an inflammatory disease caused by an autoimmune reaction. Rather, osteoarthritis is caused by the breakdown of the cartilage with age or heavy usage. Between 30 percent to 50 percent of adults over the age of 65 have osteoarthritis. Osteoarthritis is the most common form of arthritis.

How To Tell the Difference Between OA and RA

Both types of arthritis can lead to pain, stiffness, and a decrease in mobility in the joints. In RA, 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 is not necessarily symmetrical in nature since it's based on wear. In other words, one hand or wrist may be impacted, but not the other.

RA is a systemic disease that can cause general symptoms, such as fatigue and fever, as well as inflammation in other parts of the body — including the eyes, blood vessels, and the membrane that surrounds the heart. RA raises risk factors for lung disease and cardiovascular disease. Osteoarthritis is limited to the joints.

Read more details about rheumatoid arthritis symptoms.

Causes of Osteoarthritis and Rheumatoid Arthritis

Rheumatoid arthritis is an autoimmune disease in which the immune system mistakenly attacks the joints in the same way that the immune system normally would 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, redness, and warmth, as well as progressive damage.

Osteoarthritis is not 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.

Read more about causes of rheumatoid arthritis.

Diagnosing Osteoarthritis vs. Rheumatoid Arthritis

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

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

Treatment of Osteoarthritis vs. Rheumatoid Arthritis

Rheumatoid arthritis treatment options are typically aimed at modulating the immune system to calm inflammation, reduce autoimmune attacks on the joints, and ease symptoms. Nonsteroidal anti-inflammatory drugs (NSAIDs); such as Ibuprofen, Aleve (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 are designed to modulate the immune system to control the processes that cause inflammation and joint damage. In severe cases, surgery may be needed to repair or replace joints. Read more about rheumatoid arthritis treatments.

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 would not help in cases of osteoarthritis, since OA is not an autoimmune disease.

Condition Guide

• Rheumatoid Arthritis — An Overview
• Types of Rheumatoid Arthritis
• Rheumatoid Arthritis — The Path to Diagnosis
• What Causes Rheumatoid Arthritis?
• Symptoms of Rheumatoid Arthritis
• Treatments for Rheumatoid Arthritis