Differences between Rheumatoid arthritis (RA) and osteoarthritis (OA)

Is It Rheumatoid Arthritis? The Differences Between RA and OA

Rheumatoid arthritis (RA) vs. osteoarthritis (OA)

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 your 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 disorder vs. degenerative disorder

RA is an autoimmune disorder, which means your body attacks itself. If you have RA, your body interprets the soft lining around your joints as a threat, similar to a virus or bacteria, and attacks it.
This attack causes fluid to accumulate within your joint. In addition to swelling, this fluid buildup also causes:

• pain
• stiffness
• inflammation around your joints

OA, the most common form of arthritis, is a degenerative joint disorder. People with OA experience a breakdown of the cartilage that cushions their joints. The wearing down of cartilage causes the bones to rub against each other. This exposes small nerves, causing pain.
OA doesn’t involve an autoimmune process like RA does, but mild inflammation also occurs.

Risk factors

Both types of arthritis are more common in women than in men. RA and OA are more prevalent in older adults, but RA can develop at any age.
RA can run in families. You have a higher chance of developing the condition if a parent, child, or sibling has it.
You’re more likely to develop OA if you:

• are overweight
• have joint deformities
• have diabetes
• have gout
• have experienced traumatic injuries to your joints

Symptom 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

Characteristics of RA

Each kind of arthritis also has its own unique set of symptoms. RA is a systemic disease, which means it can affect your entire body — lungs, heart, eyes — and not just your joints. Early signs of RA can include:

• low-grade fever, especially in children
• muscle aches
• 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.

Characteristics of OA

People with OA are unlikely to experience overall symptoms. The degenerative nature of OA is limited solely to the joints.
You might develop lumps under the skin around joints, but these lumps are different from rheumatoid nodules. People with OA tend to develop bone spurs, or excess bone growth at the edges of the affected joints. Learn more about the symptoms of OA.