Rheumatoid Arthritis vs. Osteoarthritis: What’s the Difference?

Rheumatoid arthritis (RA) and osteoarthritis (OA) are two common types of arthritis. Both cause pain and joint damage, but they’re very different diseases.

RA is an autoimmune disease. It happens when your immune system doesn’t work the way it should. When you’re healthy, your immune system attacks invaders like bacteria and viruses. When you have RA, your immune system also “sees” your joints as enemies and launches an attack on them.

OA isn’t an autoimmune disease. You get it because the cartilage (spongy tissue) between your joints breaks down -- often due to daily wear and tear. As a result, the bones on either side of the cartilage start to change and ache.

These may be the most important differences between RA and OA. But there are many others that can help doctors know which types you have and how to treat it.

RA vs. OA Symptoms

When you see a doctor about your joint pain, you should offer as much detail as possible: what joints hurt, when they hurt, and whether you have any other symptoms. These can offer clues about whether you have RA or OA.

For instance, RA usually attacks the small joints in your hands and feet. OA is more likely to affect the ones you use most (hands and spine) and the weight-bearing ones (hips and knees).

RA tends to cause morning stiffness that can last an hour or more. That’s one of the things that really sets it apart from OA.

Other RA signs and symptoms include:

  • Fatigue
  • Low fevers
  • Low appetite
  • Lumps called rheumatoid nodules that grow under your skin (These aren’t common.)

Those things don’t usually happen in OA. With OA, your main issues are:

  • Pain and stiffness
  • Swollen joints
  • Noises (cracking, grinding) when you move the joint
  • The joint doesn’t work the way it should

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Risk Factors

RA and OA share at least a couple of risk factors. You may be more likely to get RA if you have a family member who has it. The same goes for OA. Excess weight also seems to play a role in both diseases.

Other things that raise your risk of OA include:

  • Older age
  • Joint injury
  • Overuse of a joint
  • Deformed joints, like knocked knees or legs of different lengths

The things that make RA more likely aren’t as clear. Evidence suggests that being a woman, smoking, and being around dangerous chemicals like asbestos or silica may increase your risk.

Most Common Joints Affected

OA can affect any joint, but it tends to happen in joints you’ve injured or use over and over. Think knees, hips, back, neck, thumbs, and big toes.

RA can also cause joint problems throughout your body. The disease is especially common in the small joints of your hands and feet. It also strikes shoulders, elbows, knees, and ankles. Unlike OA, RA tends to leave your back alone.

Different Drug Treatments

There’s no cure for either RA or OA, and no way to reverse joint damage. Treatments for both diseases aim to reduce pain and help the joint work better. But with RA, the main goal of treatment is to slow or stop disease activity -- to make your body stop attacking itself.

Drugs for RA:

  • Non-steroidal anti-inflammatory drugs (NSAIDs), which reduce pain and inflammation
  • Corticosteroids, which are powerful anti-inflammatories that can also help regulate your immune system
  • Disease-modifying drugs (traditional disease-modifying antirheumatic drugs, or DMARDs, and biologic drugs), which slow the course of the disease
  • Acetaminophen, which reduces pain but not inflammation

Drugs for OA:

  • Rub-on creams or gels that reduce pain
  • NSAIDs
  • Pain-relieving drugs like acetaminophen
  • The antidepressant drug duloxetine (Cymbalta), which can ease chronic pain
  • Joint injections

You may notice that opioid drugs, also known as narcotics, aren’t on either list. They’re not typically prescribed for RA and OA due to the risk of side effects over time, such as extreme tiredness, constipation, and dependency.

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Weight Loss Matters

In an ideal world, we’d all be at our healthiest weight. When you have RA or OA, reaching that health goal becomes even more important. Think of it as drug-free pain relief, not a way to look better in pants.

When you have OA: Extra weight puts extra stress on your joints, especially your knees, hips, and low back. Losing weight gives those joints some relief.

When you have RA: In addition to taking pressure off your joints, weight loss has other benefits. Research shows it can reduce disease activity -- another way of saying it slows the attack on your joints.

Diet alone may help you shed pounds, but don’t neglect gentle exercise. It can help improve your muscle strength, reduce joint pain, ease stiffness, and thus lower your disease-related disability.

Before you go on a trendy diet or join a gym, ask your doctor for advice on the best ways to approach diet and exercise when you have RA or OA.

WebMD Medical Reference Reviewed by David Zelman, MD on October 23, 2019

Sources

SOURCES:

National Institutes of Health: "Osteoporosis and Arthritis: Two Common but Different Conditions.”

American College of Rheumatology: “Osteoarthritis,” “Rheumatoid Arthritis.”

Mayo Clinic: “Rheumatoid arthritis.” 

Osteoarthritis Research Society International: "Which joints does osteoarthritis affect?”

Johns Hopkins Arthritis Center: "Rheumatoid Arthritis Signs and Symptoms.” 

International Journal of Clinical Rheumatology: Association of weight loss with improved disease activity in patients with rheumatoid arthritis.”

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