Polyarthritis, Inflammatory Arthritis, and Rheumatoid Arthritis

The terms polyarthritis, inflammatory arthritis, and rheumatoid arthritis (RA) are often used interchangeably. While they are related, they don't mean the same thing. RA is a disease, while the other two are ways of describing a particular case of arthritis (how many joints are affected and the genesis of the disease).

Polyarthritis

Polyarthritis is defined as arthritis that affects five or more joints. The term simply means that multiple joints are involved; it does not make clear what type of arthritis is at play.

Conditions that can cause polyarthritis include: 

• Rheumatoid arthritis
• Psoriatic arthritis
• Ankylosing spondylitis
• Reactive arthritis
• Spondyloarthropathies
• Lupus
• Systemic vasculitis

Treatments and the prognosis for polyarthritis depend on its specific cause.

Inflammatory Arthritis

The term inflammatory arthritis typically refers to arthritis due to autoimmune disease in multiple joints throughout the body. In autoimmune disease, your immune system misfires and attacks the body's own tissues. The damage it causes to the joint, and specifically the lining of the joint (called the synovium), leads to inflammation.

Arthritis caused by inflammation is often associated with joint pain and stiffness, especially after periods of rest or inactivity, such as in morning stiffness. Swelling, redness, and warmth may surround the affected joints.

Types of inflammatory arthritis include:

• Rheumatoid arthritis
• Psoriatic arthritis
• Ankylosing spondylitis
• Gout and pseudogout
• Lupus
• Lyme disease

As with polyarthritis, treatments and outcomes for inflammatory arthritis depend on the specific diagnosis.

Inflammatory arthritis may also be associated with systemic effects.

Rheumatoid Arthritis

Rheumatoid arthritis is a specific disease that is, by definition, a type of inflammatory polyarthritis. It's an autoimmune disease that typically involves many joints symmetrically (the same joint on both sides of the body) and may be associated with systemic effects.

Early and aggressive treatment of rheumatoid arthritis can help prevent joint damage from the inflammation. Disease-modifying anti-rheumatic drugs (DMARDs) and biologic drugs, often used in combination, are often part of the treatment regimen.

TNF blockers, which are a type of biologic drug, effectively reduce chronic inflammation, decrease mortality, and reduce the risk of cardiovascular events in people with this disease.

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A Word From Verywell

If your healthcare provider is using one of the above terms and you don't understand what it means in relation to your symptoms or diagnosis, be sure to ask. The better you understand what's going on in your body, the better armed you are to manage it, alleviate symptoms, and improve your quality of life.