Learn about rheumatoid arthritis (RA) and lupus, two conditions characterized by joint pain and stiffness. Despite some similarities, it’s easy for doctors to distinguish them. RA has more debilitating effects on the joints.

Rheumatoid arthritis (RA) and lupus are sometimes confused early on because they share certain symptoms. They’re both autoimmune diseases that affect the joints.

An autoimmune disease occurs when your immune system attacks cells in your body, triggering inflammation and damaging healthy tissue. Experts aren’t sure of all the triggers of autoimmune diseases, but they can run in families.

The most obvious similarities between RA and lupus are the joint pain and joint stiffness.

Both conditions can also cause your joints to become hot and tender, but this is more pronounced in RA.

RA and lupus both affect your energy levels, too. If you have either condition, you might feel constant fatigue or muscle weakness. Having a periodic fever is another shared symptom, but it’s more common in lupus.

Women are at greater risk of having an autoimmune disease than men, according to research such as a 2020 literature review. In addition, both RA and lupus are more likely to affect women than men.

Did you know?

Although lupus is much more common in women than men, men tend to have more severe symptoms.

There are many differences between the symptoms of RA and the symptoms of lupus.

RA primarily affects your joints, including the fingers, wrists, knees, and ankles. RA can also cause joints to become misshapen, whereas lupus usually doesn’t. Joint swelling is common in RA but rare in lupus.

Pain associated with RA is usually worse in the morning and tends to get better as the day progresses. The joint pain caused by lupus remains constant throughout the day.

RA can also be associated with these signs and symptoms:

However, with current therapies, these signs and symptoms are less common now than they’ve been in the past.

Lupus is more likely to affect your internal organs and skin than RA. Lupus can also cause life threatening complications, which may include:

These aren’t complications of RA.

Both RA and lupus can be difficult to diagnose. This is especially true early on when there are few symptoms of either condition.

Because RA and lupus share some common characteristics, people at the very early stages of either condition can also be misdiagnosed with one when they actually have the other.

Once RA has progressed a bit, doctors can easily distinguish the two.

RA can cause bone erosion and deformity if you don’t receive appropriate therapy. Lupus rarely causes bone erosion. In instances where lupus does affect the joints (such as in Jaccoud’s arthropathy), the effects are less disabling than in RA and often reversible. Jaccoud’s arthropathy is a nonerosive, inflammatory response that leads to thickening of the joint capsule.

In addition, lupus often affects the kidneys, causes anemia, or leads to weight changes. RA can also cause anemia, but lung issues occur more frequently.

Doctors can usually make a diagnosis by looking at your symptoms. However, they’ll also order blood tests to check the health of your organs and see if something else could be causing your symptoms.

RA classification criteria

Criteria used to classify these conditions in clinical trials are often used as guides for diagnosis.

For an RA diagnosis, you should receive at least 6 points on the RA classification scale devised by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR).

The scale was last updated in 2010. Points are awarded in the following manner:

  • You have symptoms that affect at least one small joint or at least two large joints (2 to 5 points).
  • The antibodies rheumatoid factor or anti-cyclic citrullinated peptide are present in your blood (2 or 3 points).
  • You have elevated levels of C-reactive protein or erythrocyte sedimentation, which are markers of inflammation (1 point).
  • Your symptoms last at least 6 weeks (1 point).

Lupus classification criteria

Systemic lupus erythematosus (SLE) is the most common type of lupus.

According to 2019 criteria from the ACR and EULAR, you must have antinuclear antibodies to receive an SLE diagnosis. In addition, you must meet at least one other criterion (some of which are included below) and accumulate at least 10 points:

Comorbidity refers to having more than one disease at the same time. This is also known as disease overlap or overlap disease.

People with RA and people with lupus can have symptoms of other conditions. It’s also possible for you to have symptoms of both RA and lupus.

There’s no limit to how many chronic conditions you can have, and there’s no time limit for when you can develop another chronic condition.

Diseases that often overlap with RA include:

Diseases that often overlap with lupus include:

There are many RA medications available to help you manage your symptoms and prevent joint damage.

Sometimes, you might need a knee or hip replacement later in life because the joint becomes too misshapen.

There’s no cure for lupus, but treatment can also help you manage your symptoms.

Many people with lupus take prescription medications to help treat joint inflammation and pain. The Food and Drug Administration (FDA) has recently approved two SLE medications:

  • belimumab (Benlysta), which is also FDA approved to treat lupus nephritis
  • anifrolumab-fnia (Saphnelo), which is taken in combination with other lupus medications

You might need medication to treat skin rashes, heart disease, or kidney problems associated with either condition. Sometimes a combination of several medications works best.

In rare cases, people with either condition might get cortisone shots to manage the inflammation. Corticosteroids are only used rarely now because of the high risk of side effects.

If you have either RA or lupus, you’ll need to make a long-term plan with a doctor or healthcare professional. This plan will include ways to help manage the inflammation and pain. It will also help you minimize complications.

Complications of untreated RA include:

  • permanent joint deformity
  • anemia
  • lung damage

Treatment can help prevent long-term issues.

Long-term complications of lupus include heart and kidney damage. People with lupus often have conditions affecting their blood, including anemia and inflammation of the blood vessels. Proper treatment of lupus can help prevent tissue damage.