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.

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:

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.

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:

Many of the basic symptoms of RA and OA are the same, including:

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:

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.

“Fatigue was my first major symptom. They did all sorts of tests, including testing my thyroid. Then, they suggested an HIV test. When joint paint started, they thought it was a blood clot in my knee. Finally, I was referred to a rheumatologist.”—Anonymous, living with rheumatoid arthritis

RA and OA may affect different joints.

Affected joints in RA

RA usually begins in the smaller joints. You’re likely to have pain, stiffness, and swelling in the finger joints. As RA progresses, symptoms can develop in larger joints such as 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.

Affected joints in OA

OA is less symmetrical. You might have pain in both your 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 in treating both OA and RA is to:

  • reduce pain
  • improve function
  • minimize damage to your joints

Your doctor will approach these goals differently, depending on which condition you have.

Anti-inflammatory and corticosteroid medications are generally effective for both OA and RA. If you have RA, drugs that suppress your immune system can prevent damage by stopping your body from attacking your joints.

There’s no cure for RA or OA. However, treatments are available to manage the symptoms of both conditions.

Contact your doctor if you think you’re experiencing symptoms of RA or OA. They can refer you to a specialist to help manage your condition and find treatment.