Polyarthritis, Inflammatory Arthritis, and Rheumatoid Arthritis

Are They the Same?

Woman rubbing her arthritic hand
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There are many types of arthritis and terminology which pertain to the conditions can get confusing. Polyarthritis, inflammatory arthritis, and rheumatoid arthritis are examples. Often the terms are used interchangeably but are they really the same? Let's consider each separately and determine the answer.


Polyarthritis refers to arthritis that affects more than four joints. Polyarthritis usually results in polyarthralgia, which is pain in more than four joints.

Therefore, polyarthritis describes a pattern of joint involvement, but it is not a specific type of arthritis.  

Inflammatory Arthritis

Inflammatory arthritis typically affects several joints throughout the body simultaneously. It is caused by an overactive immune system whereby the body attacks its own tissues (autoimmune disease), resulting in joint inflammation. Arthritis caused by inflammation is often associated with joint pain and stiffness, especially after periods of rest or inactivity (e.g., morning stiffness). There can be swelling, redness, and warmth around the affected joints, too. Inflammatory arthritis may be associated with systemic effects. Rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis are types of inflammatory arthritis.

Rheumatoid Arthritis

Rheumatoid arthritis is a specific disease, a type of inflammatory polyarthritis.

Rheumatoid arthritis is an autoimmune disease that typically involves many joints symmetrically (i.e., same joint on both sides of the body). Rheumatoid arthritis may also be associated with systemic effects.

The Bottom Line

Synonymous terms are equivalent in meaning. Based on that definition, polyarthritis, inflammatory arthritis, and rheumatoid arthritis,are not synonymous -- but they are definitely related.

All three terms may appropriately be used to describe rheumatoid arthritis. Rheumatoid arthritis is an inflammatory type of arthritis and can be described as polyarthritis if more than 4 joints are involved.

Inflammatory arthritis does not exclusively refer to rheumatoid arthritis. Psoriatic arthritis, ankylosing spondylitis, and juvenile idiopathic arthritis are also inflammatory types of arthritis.

Remember, polyarthritis refers to how many joints are affected. Inflammatory arthritis refers to several types of arthritis that are associated with inflammation. Rheumatoid arthritis is a specific type of arthritis.


Primer on the Rheumatic Diseases. Arthritis Foundation. Thirteenth Edition.

Understanding Inflammatory Arthritis. Hospital for Special Surgery. 4/7/2015.

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