Joint pain is the hallmark of rheumatoid arthritis (RA), but it is also common in several other conditions, such as:
- Spondyloarthropathies, such as ankylosing spondylitis
- Crystal arthritis, such as gout
- Autoimmune conditions, such as lupus
- Infectious arthritis
Many of these conditions cause joint inflammation, fever, and/or fatigue, just like rheumatoid arthritis.
Doctors diagnosing the cause of painful joints look for clues that help distinguish the patient’s condition from other conditions, ruling out each possible diagnosis until only one is left.
The process of distinguishing one disease from others that cause similar symptoms is sometimes called the “differential diagnosis.” In some cases, this process can take several weeks or months and require lab tests and visits to specialists.
Fibromyalgia vs. Rheumatoid Arthritis (RA)
This condition occurs when the brain overreacts to pain signals, intensifying feelings of pain in different parts of the body. Fibromyalgia and rheumatoid arthritis are separate diseases, but some people have both.
How is it similar to RA? Fibromyalgia can cause musculoskeletal pain as well as debilitating mental and physical fatigue. Like RA, fibromyalgia is more common in women and runs in families, but the exact cause is unknown. Both are chronic in nature and can have periods of exacerbation and remission.
How is it different? Fibromyalgia typically does not cause swelling (except in children). It often causes tenderness in specific areas of the body, called tender points. Fibromyalgia is not a degenerative condition and does not cause joint erosion and deformity.
Osteoarthritis vs. Rheumatoid Arthritis
Osteoarthritis occurs when the cartilage that acts as padding between the joints breaks down. The cartilage can wear down gradually, over decades—in fact, osteoarthritis is sometimes referred to as degenerative joint disease. When cartilage degeneration is triggered by an injury it is called post-traumatic osteoarthritis. Osteoarthritis is by far the most common type of arthritis.
How is it similar to RA? Osteoarthritis is characterized by joint pain that is worse after periods of inactivity. Joints may feel stiff and lose range of motion. Sometimes an affected joint is swollen and/or tender to the touch.
How is it different? Although some people with osteoarthritis experience joint swelling, the swelling is usually mild and less notable than the moderate to severe joint swelling that is a hallmark of RA. Because osteoarthritis is not a systemic (body-wide) autoimmune disease like rheumatoid arthritis, it is not accompanied by fatigue, fever, or flu-like symptoms.