Autoimmune diseases like Lupus, Scleroderma, and Psoriatic Arthritis (PsA) often mimic rheumatoid arthritis (RA) by causing joint pain, swelling, and stiffness, but can also involve skin rashes, fatigue, or affect internal organs, requiring careful diagnosis to distinguish from RA's primary joint focus. Other mimics include fibromyalgia, autoimmune thyroid disease, and even infections like Lyme disease, making early and accurate diagnosis by a rheumatologist crucial.
Other diseases that cause joint pain and inflammation can sometimes be misdiagnosed as rheumatoid arthritis (RA). These include conditions such as osteoarthritis, lupus, and Lyme disease. A diagnosis may involve testing not just for RA but to rule out other conditions, as well.
Rheumatoid arthritis is an autoimmune disease. This means your immune system (which usually fights infection) attacks the cells that line your joints by mistake, making the joints swollen, stiff and painful. Over time, this can damage the joints, cartilage and nearby bone.
Once activated, OA joint cells in turn release inflammatory mediators into the joint cavity and eventually into the blood. The mediators amplify the low-grade inflammation, which may induce or accelerate other chronic diseases affected by systemic low-grade inflammation.
Rheumatoid arthritis (RA) is a chronic (long-lasting) autoimmune disease that mostly affects joints. RA occurs when the immune system, which normally helps protect the body from infection and disease, attacks its own tissues. The disease causes pain, swelling, stiffness, and loss of function in joints.
Autoimmune and rheumatic diseases are diagnosed based mainly on a thorough medical history and physical exam, with some input from imaging and lab tests. Blood tests may provide clues, but they don't confirm or rule out a particular type of arthritis, and tests sometimes have false results.
Psoriatic arthritis also may cause:
Blood tests
People with rheumatoid arthritis often have an elevated erythrocyte sedimentation rate (ESR), also called sed rate, or C-reactive protein (CRP) level. This may show a higher level of inflammation in the body.
RA is symmetrical, where a patient feels symptoms in the same spot on both sides of the body, often in the joints in the feet and hands. Osteoarthritis, in contrast, begins in an isolated joint, often in the knee, fingers, hands, spine and hips. While both sides may hurt, one side is more painful.
“Our study demonstrates that a drug already commonly used for rheumatoid arthritis, methotrexate, might help the pain of osteoarthritis, and also gives us a clue about which subset of patients, those with elevated blood inflammation levels, might get benefit from this therapy.”
When lupus, a systemic autoimmune disease, affects the joints, it can cause symptoms similar to RA. Most people with lupus also experience flares, where symptoms get worse, then improve or disappear. Other similar signs of lupus and RA include fatigue, fever, and dry eyes.
Three key signs of Sjögren's syndrome are dry eyes, dry mouth, and chronic fatigue, stemming from the autoimmune system attacking moisture-producing glands, leading to gritty, burning eyes, difficulty swallowing or speaking, and persistent tiredness, often accompanied by joint pain and swollen glands.
Key Points. Acute pain in multiple joints is most often due to inflammation, gout, or the beginning or flare up of a chronic joint disorder. Chronic pain in multiple joints is usually due to osteoarthritis or an inflammatory disorder (such as rheumatoid arthritis) or, in children, juvenile idiopathic arthritis.
It might be — or it might be a condition that simply has symptoms that can be confused with arthritis symptoms, such as lupus or fibromyalgia. Or maybe it's a condition that can occur with arthritis, like eye inflammation, skin conditions or heart and lung diseases.
Rheumatoid arthritis can be difficult to diagnose because many conditions cause joint stiffness and inflammation and there's no definitive test for the condition.
In this test, the second through fourth metacarpophalangeal joints (see image, lower left) or the metatarsophalangeal joints (see image, lower right) are squeezed together to test for tenderness. A positive result raises the question of an inflammatory arthritis such as rheumatoid arthritis.
Drug therapies include oral pain relievers such as acetaminophen or nonsteroidal anti-inflammatory drugs (often called NSAIDs), which decrease swelling and pain. Cymbalta is also sometimes prescribed to reduce pain, and patients with more serious pain may need stronger medications, such as prescription narcotics.
Osteoarthritis tends to cause stiffness and pain in specific joints (that usually gets worse with activity), while rheumatoid arthritis typically affects multiple joints at the same time. Some symptoms that overlap both conditions include: Joint pain. Joint stiffness.
Although there's no blood test for osteoarthritis, certain tests can help rule out other causes of joint pain, such as rheumatoid arthritis. Joint fluid analysis. A needle might be used to draw fluid from an affected joint.
Laboratory tests
The analysis of different types of body fluids can help pinpoint the type of arthritis you may have. Fluids commonly analyzed include blood, urine and joint fluid. To obtain a sample of joint fluid, doctors cleanse and numb the area before inserting a needle in the joint space to withdraw some fluid.
Gout is an extremely painful type of arthritis caused by a buildup, overflow and/or inability to process uric acid.
The degree of elevation of these acute phase reactants varies with the severity of inflammation and synovitis. As an example, an ESR of 50 to 80 is not uncommon in patients with severely active RA. By comparison, an ESR of 20 to 30 can be observed with only a few mildly to moderately active joints.
What's the First Red Flag of Psoriatic Arthritis? Many people get psoriasis, the skin disease first. However, joint pain, swelling and stiffness—particularly in the morning–are often the first hallmark signs of the disease.
Symptoms specifically related to the inflamed arteries of the head include:
Palindromic rheumatism (pal-in-drom-ic roo-ma-tiz-em) is a form of inflammatory arthritis. It causes attacks or flare-ups of joint pain and inflammation that come and go.