Arthritis is an umbrella term used to describe inflammation of the joints. However, there are different kinds of arthritis, including rheumatoid arthritis (RA) and osteoarthritis (OA).
Although RA and OA both affect the joints, they’re very different forms of the same broader condition. RA is an autoimmune condition, while OA is primarily a degenerative joint condition.
Autoimmune vs. Degenerative Disease
RA is an autoimmune disease, which means your body attacks itself. In people with RA, the body interprets the synovium, the soft lining around the joints, as a threat similar to a virus or bacteria and attacks it. This attack causes fluid to accumulate within the joint. The fluid buildup causes swelling, pain, stiffness, and inflammation around your joints.
OA, the most common form of arthritis, is a degenerative joint disease. People with OA experience a breakdown of the cartilage that cushions the joints. The wearing down of cartilage causes your bones to rub against each other exposing small nerves, which causes pain. OA does not involve an autoimmune process like RA does, but mild inflammation also occurs.
People who are overweight, suffer from joint deformities, diabetes, or gout are more likely to develop OA. RA can run in families.
Similarities and Differences
Many of the basic symptoms of RA and OA are the same, including:
- painful, stiff joints
- limited range of motion
- warmth or tenderness in the affected area
- increased intensity of symptoms first thing in the morning
Each kind of arthritis also has its own unique set of symptoms. RA is a systemic disease, which means it can affect the entire body, not just the joints. Early signs of RA can include low-grade fever (in children), muscle aches, and excessive fatigue.
People in advanced stages of RA may notice hard lumps underneath the skin near joints. The lumps, called rheumatoid nodules, can be tender.
People with OA are not likely to experience body-wide symptoms. The degenerative nature of OA is limited solely to the joints. It doesn’t affect the entire body.
You might develop lumps under the skin around the joints, but these lumps are different from rheumatoid nodules. People with OA tend to develop excess bone growth at the edges of the affected joints, called bone spurs.
RA usually begins in the smaller joints of the body. You’re likely to have pain, stiffness, and swelling in the finger joints. As RA progresses, symptoms can develop in the larger joints such as the knees, shoulders, and ankles.
RA is a symmetrical disease. That means you’ll experience symptoms on both sides of your body at the same time.
OA is less symmetrical. You might have pain in both the left and right knee, for example, but one side or one joint is worse. OA, like RA, is common in the hand and fingers. OA often affects the spine and hips in addition to the knees.
The primary goal for both OA and RA is to reduce pain, improve function, and minimize damage to the joints. Your doctor will approach these goals differently, depending on which form of the disease you have.
Anti-inflammatory and corticosteroid medications are generally effective for both OA and RA. Drugs that suppress the immune system stop the immune system from attacking the joints in those with RA, preventing damage.
There is no cure for RA or OA. However, treatments are available to make the symptoms of both conditions manageable. Contact your doctor if you think you’re experiencing symptoms of RA or OA. They can recommend you to a specialist.