Table of ContentsView AllTable of ContentsOsteoarthritisLupus and SclerodermaSjögren’s DiseasePsoriatic ArthritisViral ArthritisLyme DiseaseFibromyalgiaGoutReactive ArthritisBursitisSarcoidosisPolymyalgia RheumaticaHemochromatosisDual Diagnosis
Table of ContentsView All
View All
Table of Contents
Osteoarthritis
Lupus and Scleroderma
Sjögren’s Disease
Psoriatic Arthritis
Viral Arthritis
Lyme Disease
Fibromyalgia
Gout
Reactive Arthritis
Bursitis
Sarcoidosis
Polymyalgia Rheumatica
Hemochromatosis
Dual Diagnosis
A number of diseases mimic the symptoms ofrheumatoid arthritis(RA), anautoimmuneform of arthritis. These include bacterial joint infections, inflammatory diseases, other autoimmune diseases, andother forms of arthritis.
Ruling out conditions that mimic RA is central to thediagnosis of RA. To do so, your healthcare provider will not only order tests that point to RA as the cause but also order tests to exclude other diseases like Lyme disease, lupus, or fibromyalgia.
Even if you’ve been diagnosed with RA, your healthcare provider may want to investigate other possible causes if you are not responding toRA treatmentor if there is a chance that another disease is co-occurring with RA (referred to as acomorbidity).
This article describes 14 conditions that mimic rheumatoid arthritis along with comorbid conditions that commonly occur alongside RA.
Signs and Symptoms of Rheumatoid Arthritis
Verywell Health / Hilary Allison
Did You Know?Research published in theAnnals of Rheumatic Diseasesfound that more than 40% of people who were diagnosed with RA actually have a different condition.
Did You Know?
Research published in theAnnals of Rheumatic Diseasesfound that more than 40% of people who were diagnosed with RA actually have a different condition.
Osteoarthritis(OA), is a degenerative joint disease that can be similar to RA. It is the most common form of the disease, often referred to as “wear-and-tear arthritis.”
There are some key differences between OA and RA:
Blood and imaging tests can help ensure an accurate diagnosis. These include:
RA and OA also have distinctly different patterns on X-ray which help determine which type of arthritis is involved.
OA vs. RA: How They Differ
Systemic lupus erythematosus(lupus) andsclerodermaare two autoimmune diseases that can mimic rheumatoid arthritis. Autoimmune diseases are those in which the body’s immune system attacks its own cells and tissues.
With lupus, the attack is systemic (affecting multiple organ systems are affected), while scleroderma primarily affects the skin and joints.
Lupus and scleroderma differ from RA in that the tendons and ligaments surrounding the joints are the primary targets of the assault. With RA, the inflammation occurs in the lubricating fluid within joint spaces (calledsynovial fluid), leading to the progressive destruction of joint cartilage.
Because RF and anti-CCP tests are also typically elevated with RA, lupus, and scleroderma, a third test, called theantinuclear antibodies (ANA) test,may help differentiate the diseases. With lupus and scleroderma, ANA results will almost invariably be high, while the results with RA can vary.
Other signs of lupus and scleroderma uncommon with RA include:
Sjögren’s disease (SjD), previously known as Sjögren’s syndrome), is another autoimmune disease that primarily affects moisture-producing glands called thesalivaryandlacrimal glands. Sjögren’s can also affect other organ systems as well, most notably the joints.
Joint pain is one of the more common symptoms of Sjögren’s. Multiple joints are typically affected, causing sudden and severe episodes of pain, swelling, and tenderness. As with RA, joints on both sides of the body are affected at the same time.
With Sjögren’s, the joints of the knees, wrists, and fingers are most commonly affected.With RA, the joints of the hands, wrists, and feet are mainly affected alongside with shoulders, elbows, knees, and ankles.
Sjögren’s disease can be hard to distinguish from RA because many of the standard tests will deliver the same or similar results. Moreover, many people with Sjögren’s also have RA, further complicating the diagnosis.
One test that can help differentiate the diseases is theanti-SSA/Ro test(also known as the Sjögren antibody test). While the test will show elevated anti-SSA antibodies in about 50% of people with Sjögren’s, they may be elevated with other autoimmune diseases, such as lupus and even RA.
Psoriatic arthritis (PSA)is a type of arthritis linked to the autoimmune skin conditionpsoriasis. PSA can closely mimic RA, but can often be differentiated through blood tests.
Since high levels of RF and anti-CCP are typically present in RA, these results are consideredseropositive.
PsA can have low levels of RF but no anti-CCP antibodies, making these indicatorsseronegative.
Both RA and PsA can start in the fingers and toes. However, PsA and otherspondyloarthropathiesare more likely to go on to affect the spine and thesacroiliacjointsthan RA.
Other key characteristics of PsA that help differentiate it from RA include:
Who Treats Osteoporosis?
Viral infections such asrubella,parvovirus B19,HIV, andhepatitisB and C can cause pain and swelling in multiple joints (polyarthritis) and present in a way that’s clinically similar to rheumatoid arthritis.
Your healthcare provider can take blood work to rule out different viral and bacterial causes of joint pain. Treatment for viral arthritis is normally focused on pain management. AndHIV-triggered arthritiscan be relieved with combination antiretroviral therapy.
Most cases of viral arthritis resolve on their own after several weeks.
Viruses and Arthritis
Left untreated, Lyme disease results in chronic arthritis with severe joint pain and swelling, particularly in the knees and other large joints.
Other signs of Lyme disease that aren’t present in RA include:
Lyme disease is diagnosed based on antibodies, which can be identified with a blood sample. It takes several weeks for the immune system to develop enough antibodies to be detected, so a recent infection may not produce a positive test. If you might have this condition, the test is usually repeated in about six weeks.
Early treatment of Lyme disease with antibiotics typically results in complete recovery, though symptoms can linger for up to six months. A delay in antibiotic treatment can make the disease more difficult to treat and may result in chronic symptoms and pain, so it’s important that any symptoms be investigated early.
Imaging studies are useful for distinguishing the conditions becausesynovitis(inflammation of joint lining) is present with RA and absent with fibromyalgia.
Fibromyalgia also differs from RA because it causes:
Fibromyalgia can be difficult to diagnose. There are no specific tests to confirm a diagnosis and, much like with RA, it is important to rule out other possible conditions.
Crystal-deposition diseases likegoutandpseudogoutare often mistaken for RA. With these conditions, uric acid crystal deposits settle around affected joints, resulting in inflammation and tissue damage.
Gout tends to appear as painful, swollen joints associated with asymmetric inflammation in one or more fingers or toes. A gout attack commonly affects the large toe and lasts for three to 10 days.
Over time, gout attacks can become more frequent, last longer, and may not resolve. This can lead to chronic gouty arthropathy, which can cause erosions and joint destruction.
Calcium pyrophosphate deposition disease (CPPD) or pseudogout (false gout) is a type of arthritis that can present similarly to gout or RA but is distinguishable from acute gout attacks.
Tests your healthcare provider may perform to differentiate between gout, CPPD, and RA include blood tests for uric acid, imaging tests, andsynovial fluid analysis.
Gout vs. Rheumatoid Arthritis: What Are the Differences?
Previously known as Reiter’s syndrome, reactive arthritis is in the family of seronegative spondyloarthropathies. Symptoms generally appear within a month of a bout ofdiarrheaor agenital infection.
A blood test can identify bacterial infections, such asChlamydia trachomatis,Campylobacter,Salmonella,Shigella, orYersinia.
Bursitis typically affects only one joint at a time—commonly the knee, elbow, or shoulder—and does not have the systemic symptoms of RA.
Diagnosis is based on physical examination and imaging tests such as X-rays or MRIs. Your healthcare provider may sample fluid from the swollen area to rule out an infection as well.
An Overview of Bursitis
Like RA, sarcoidosis onset typically occurs between ages 30 and 50.
Other characteristics of sarcoidosis that help to distinguish it from RA include:
Sarcoidosis is formally diagnosed through biopsy.
What Is Sarcoidosis?
Polymyalgia Rheumatica and Giant Cell Arteritis
Polymyalgia rheumatica(PMR) andgiant cell arteritis(GCA) are closely linked inflammatory conditions that almost always occur in people over 50 years old. These conditions affect joints and might mimic RA.
PMR causes muscle pain and stiffness in the shoulders, upper arms, hip area, and sometimes the neck. GCA is a type of vasculitis that can cause symmetrical pain and tenderness in multiple joints.In addition, people with vasculitis often test positive for rheumatoid factor.
A key difference is that GCA commonly presents with headaches. A detailed medical history can help distinguish PMR or GCA from RA.
In some cases, a diagnosis of vasculitis may depend on observation of the disease over time, particularly if complications develop.
Vasculitis: Treatment for Autoimmune Symptoms
Other causes include severe liver disease and receiving multiple blood transfusions.
Hemochromatosis can cause arthritis, among other problems. The joint pain notably affects the knuckles of the index and middle fingers. The joints may be swollen and have reduced range of motion, but are not inflamed.
Large joints such as the knees, hips, ankles, elbows, and shoulders may also be painful. The presence of pain in the ankles and wrists can help healthcare providers distinguish hemochromatosis from other causes of arthritis.
People with hemochromatosis also have other symptoms, including:
The condition can lead to a range of complications due to the organ damage the iron causes, such as liver disease or cancer, heart failure, diabetes, and hypothyroidism.
You may be so used to living with RA that you chalk up any change in your symptoms to the disease, rather than another possible cause.
If you are experiencing an unusual persistence of or increase in your RA symptoms, or if new ones appear, check in with your healthcare provider. Additional diagnoses can be considered and, at the very least, you can be evaluated to see if your RA treatment plan needs to be modified.
While it’s possible that you could also have any of the common RA mimics, the most common RA comorbidities—which may or may not have similar symptoms—include:
Summary
Joint pain, a common symptom of many conditions that can mimic rheumatoid arthritis, may complicate the diagnosis. If you aren’t improving with treatment, talk to your healthcare provider. You might need additional testing or a referral to arheumatologistor other specialist. Ensuring an accurate diagnosis is essential for finding a treatment that works for you.
The Differences Between RA and Other Types of Arthritis
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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Centers for Disease Control and Prevention.Rheumatoid arthritis (RA).Taylor PC.Update on the diagnosis and management of early rheumatoid arthritis.Clin Med (Lond).2020 Nov;20(6):561–564. doi:10.7861/clinmed.2020-0727Santos-Moreno P, Bello J, Cubides M,et al.AB1000 Rheumathoid arthritis misdiagnosis and osteoarthritis as the most frequent cause for diagnosis mistake.Ann Rheum Dis.2013;71:695. doi:10.1136/annrheumdis-2012-eular.1000Myositis Association.Overlapping autoimmune diseases.Stefanski AL, Tomiak C, Pleyer U, Dietrich T, Burmester GR, Dörner T.The diagnosis and treatment of Sjögren’s syndrome.Dtsch Arztebl Int.2017;114(20):354-361. doi:10.3238/arztebl.2017.0354National Institute of Arthritis and Musculoskeletal and Skin Diseases.Psoriatic arthritis.Marks M, Marks JL.Viral arthritis.Clin Med (Lond). 2016;16(2):129–134. doi:10.7861/clinmedicine.16-2-129Miner JJ, Aw-Yeang HX, Fox JM, et al.Chikungunya viral arthritis in the United States: a mimic of seronegative rheumatoid arthritis.Arthritis Rheumatol. 2015;67(5):1214-1220. doi:10.1002/art.39027Centers for Disease Control and Prevention.Lyme disease.Centers for Disease Control and Prevention.Signs and symptoms of untreated lyme disease.Centers for Disease Control and Prevention.Clinical testing and diagnosis for lyme disease.MedlinePlus.Fibromyalgia.Arthritis Foundation.Gout.American College of Rheumatology.Reactive arthritis.MedlinePlus.Bursitis.MedlinePlus.Sarcoidosis.National Institute of Arthritis and Musculoskeletal and Skin Diseases.Polymyalgia rheumatica and giant cell arteritis.Sangolli PM, Lakshmi DV.Vasculitis: a checklist to approach and treatment.Indian Dermatol Online J.2019 Nov-Dec;10(6):617–626. doi:10.4103/idoj.IDOJ_248_18National Institute of Diabetes and Digestive and Kidney Diseases.Definition & Facts for Hemochromatosis.Carroll GJ, Breidahl WH, Olynyk JK.Characteristics of the arthropathy described in hereditary hemochromatosis.Arthritis Care Res (Hoboken). 2012;64(1):9-14. doi:10.1002/acr.20501Kłodziński Ł, Wisłowska M.Comorbidities in rheumatic arthritis.Reumatologia. 2018;56(4):228-233. doi:10.5114/reum.2018.77974
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Taylor PC.Update on the diagnosis and management of early rheumatoid arthritis.Clin Med (Lond).2020 Nov;20(6):561–564. doi:10.7861/clinmed.2020-0727
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Myositis Association.Overlapping autoimmune diseases.
Stefanski AL, Tomiak C, Pleyer U, Dietrich T, Burmester GR, Dörner T.The diagnosis and treatment of Sjögren’s syndrome.Dtsch Arztebl Int.2017;114(20):354-361. doi:10.3238/arztebl.2017.0354
National Institute of Arthritis and Musculoskeletal and Skin Diseases.Psoriatic arthritis.
Marks M, Marks JL.Viral arthritis.Clin Med (Lond). 2016;16(2):129–134. doi:10.7861/clinmedicine.16-2-129
Miner JJ, Aw-Yeang HX, Fox JM, et al.Chikungunya viral arthritis in the United States: a mimic of seronegative rheumatoid arthritis.Arthritis Rheumatol. 2015;67(5):1214-1220. doi:10.1002/art.39027
Centers for Disease Control and Prevention.Lyme disease.
Centers for Disease Control and Prevention.Signs and symptoms of untreated lyme disease.
Centers for Disease Control and Prevention.Clinical testing and diagnosis for lyme disease.
MedlinePlus.Fibromyalgia.
Arthritis Foundation.Gout.
American College of Rheumatology.Reactive arthritis.
MedlinePlus.Bursitis.
MedlinePlus.Sarcoidosis.
National Institute of Arthritis and Musculoskeletal and Skin Diseases.Polymyalgia rheumatica and giant cell arteritis.
Sangolli PM, Lakshmi DV.Vasculitis: a checklist to approach and treatment.Indian Dermatol Online J.2019 Nov-Dec;10(6):617–626. doi:10.4103/idoj.IDOJ_248_18
National Institute of Diabetes and Digestive and Kidney Diseases.Definition & Facts for Hemochromatosis.
Carroll GJ, Breidahl WH, Olynyk JK.Characteristics of the arthropathy described in hereditary hemochromatosis.Arthritis Care Res (Hoboken). 2012;64(1):9-14. doi:10.1002/acr.20501
Kłodziński Ł, Wisłowska M.Comorbidities in rheumatic arthritis.Reumatologia. 2018;56(4):228-233. doi:10.5114/reum.2018.77974
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