Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Select An Article

What Causes Rheumatoid Arthritis?

Font Size

Unlike osteoarthritis, a condition caused by wear and tear on joints, rheumatoid arthritis happens when your immune system targets your joint linings. It’s a long-term condition that also affects other tissue, but the joints are usually the most severely affected.

Doctors don’t know exactly what causes RA. It may be a combination of genes and other things. Some researchers think an infection with a bacteria or virus can trigger the disease in some people, but so far, they don’t know what virus or other organism does that.

As rheumatoid arthritis develops, some of the body's immune cells start to attack healthy tissue, mistaking it for an invader. This triggers a chain reaction that leads to more inflammation and damage.

The main target of RA's inflammation is the synovium, the thin layer of tissue that lines the joints. The inflammation also spreads to other areas in the body, which can cause ongoing pain, fatigue, and other problems.

What Makes Me More Likely to Get Rheumatoid Arthritis?

The disease is more common in women than in men. It’s more likely in women who've never been pregnant and in those who've recently given birth.

The condition can also run in families.

RA becomes more likely with age, too, but it’s not a normal part of aging. Cigarette smoking may also raise your chances of getting it.

WebMD Medical Reference

Reviewed by David Zelman, MD on May 26, 2014
Next Article:

Today on WebMD

rubbing hands
Avoid these 6 common mistakes.
mature couple exercising
Decrease pain, increase energy.
mature woman threading needle
How much do you know?
Swelling, fatigue, pain, and more.
Lucille Ball
Hand bones X-ray
prescription pills
Woman massaging her neck
woman roasting vegetables in oven
Woman rubbing shoulder
doctor and patient hand examination