Written by Diana Bocco
Medically Reviewed by Nancy Carteron, MD, FACR
What are autoimmune diseases?
Autoimmune disease occurs when your immune system attacks cells in your body, triggering inflammation and damaging healthy tissue. Scientists aren’t sure of all the triggers of autoimmune diseases, but they can run in families.
Women are at greater risk of having an autoimmune disease than men. African-American, Native-American, and Hispanic women have even greater risk, according to the National Institutes of Health.
What are lupus and RA?
The most obvious similarity between RA and lupus is joint pain. Joint swelling is another common symptom, though with varying levels of inflammation. Both diseases also cause your joints to become hot and tender, but this is more pronounced in RA.
Lupus and RA affect your energy levels, as well. If you have either disease, you might feel constant fatigue or weakness. Having a periodic fever is another symptom of both lupus and RA, but it’s more common in lupus.
Both diseases are more common in women than men.
How to tell them apart
There are many differences between lupus and RA. For instance, lupus might attack your joints, but it’s more likely to affect your internal organs and your skin than RA. Lupus can cause life-threatening complications.
RA, on the other hand, mainly attacks your joints. It primarily affects the fingers, wrists, knees, and ankles. RA can also cause joints to deform, while lupus usually doesn’t.
Pain associated with RA is usually worse in the morning and tends to get better as the day progresses. But the joint pain caused by lupus is more constant throughout the day, and it can migrate.
Why the diseases are often confused
Because these two diseases share some common characteristics, people can be misdiagnosed with RA when they actually have lupus, or vice versa.
Once RA is advanced, doctors can tell because the disease causes bone erosion and deformity. Lupus, however, rarely affects the bones the same way.
In the early stages of RA or lupus, doctors can usually make a diagnosis by looking at your symptoms. For example, lupus often affects the kidney, causes anemia, or leads to weight changes. A doctor might order a blood panel to check the health of your organs and to see if there’s something else that could be causing the symptoms.
Part 3 of 6: Diagnosis
Both lupus and rheumatoid arthritis can be difficult to diagnose. This is especially true early on when there are few symptoms.
To be diagnosed with systemic lupus, you must meet at least four of the 11 criteria. The diagnostic criteria are:
- malar rash: a rash, also known as the butterfly rash, that appears on the cheeks and nose
- discoid lupus: raised red patches on the skin
- photosensitivity: developing a skin rash when you’re exposed to sunlight
- arthritis: arthritis that doesn’t cause bone erosion
- heart and lung changes: inflammation of the lining of the heart or lungs
- neurological symptoms: seizure or psychosis
- kidney symptoms: protein or cellular casts in the urine
- blood disorders: anemia, low white blood cell count, or low platelet count
- immunologic disorder: antibodies to double stranded DNA, Sm, or cardiolipin
- presence of antinuclear antibodies, or ANA
To be diagnosed with RA, you must get at least six points on the RA classifications scale. The scale is:
- symptoms that affect at least one or more joints (up to five points)
- testing positive for rheumatoid factor or anticitrullinated protein antibody in your blood (up to three points)
- positive C-reactive protein (CRP) or erythrocyte sedimentation tests (one point)
- symptoms lasting longer than six weeks (one point)
Part 4 of 6: Disease overlap
Comorbidity refers to having more than one disease at the same time. This is also known as overlap disease. People with lupus and people with RA can have symptoms of other conditions. It’s also possible for people to have symptoms of RA and lupus.
There’s no limit to how many chronic conditions you can have, and there is no time limit for when you can develop another chronic condition.
Diseases that often overlap with lupus include:
- mixed connective tissue disease
- autoimmune thyroid
Diseases that often overlap with RA include:
- autoimmune thyroid
Part 5 of 6: Treatment
There is no cure for lupus, but treatment can help you manage your symptoms. Many people with lupus take corticosteroids and other prescription drugs to treat joint inflammation and pain. Others might need medication to treat skin rashes, heart disease, or kidney problems. Sometimes a combination of several drugs works best.
People with rheumatoid arthritis can get cortisone shots to control the inflammation. Sometimes, patients might need a knee or hip replacement later in life because the joint becomes too deformed. Many medications are available to control symptoms and prevent joint damage.
Part 6 of 6: Outlook
What you can expect
People with both lupus and RA will need to make a long-term plan with their doctors. This plan will include ways to help control the inflammation and pain. It will also help you minimize the complications of lupus and RA.
Long-term complications of lupus include heart and kidney damage. Lupus patients often suffer from abnormalities of the blood, including anemia and inflammation of the blood vessels. Without treatment, all of these can damage tissue.
Complications of untreated RA include permanent joint deformity.