Like rheumatoid arthritis (RA), Sjögren’s syndrome (pronounced SHOW-grins, sometimes called SS) is an autoimmune disease. If you have been diagnosed with RA, your rheumatology team may also have you screened for Sjögren’s syndrome. This is because RA is associated with a higher risk of developing other autoimmune diseases, including Sjögren’s syndrome. According to research, about half of people diagnosed with Sjögren’s syndrome have also been diagnosed with a rheumatic condition like RA.
If you have — or are suspected of having — both RA and Sjögren’s, it may be difficult to tell them apart. Here is what you need to know about the relationship between RA and Sjögren’s syndrome, including their key differences and similarities.
Sjögren’s syndrome is an immune system disorder (autoimmune disease). This means it occurs when the immune system mistakenly attacks the body’s healthy tissues. It most commonly targets the parts of the body responsible for producing fluids, like saliva and tears.
The characteristic symptoms of Sjögren’s syndrome are dry mouth and dry eyes. These are referred to as sicca symptoms. However, Sjögren’s syndrome can also target other areas of the body, causing vaginal dryness in women, as well as swollen salivary glands, dry skin, muscle and joint pain, and exhaustion.
Although it is also an autoimmune disease, RA targets the synovium — the tissue that lines the joints. This causes joint pain and inflammation. Like Sjögren’s syndrome, however, it can also affect other body systems, including the skin, blood vessels, and other organs.
“Pathophysiology” is a term used to describe the biological processes that cause disease. The pathophysiology of autoimmune disease is not completely understood, but several underlying mechanisms of autoimmune disorders have been identified.
Certain risk factors affect a person’s likelihood of developing autoimmune diseases. Research has found that certain genes can put people at higher risk of developing both Sjögren’s syndrome and RA. In Sjögren’s syndrome, in particular, it also appears that there must be a specific trigger — like an infection with certain viruses or bacteria — before the syndrome develops.
Sjögren’s syndrome is usually diagnosed in women over the age of 40, many of whom have also been diagnosed with rheumatic diseases, like RA or lupus. It can occur by itself (which is called primary Sjögren’s syndrome) or with other autoimmune conditions.
People are at a higher risk of being diagnosed with both RA and Sjögren’s syndrome if they are older and female. They are also more likely to be diagnosed with both conditions if their RA involves their internal organs, particularly their lungs, or if they have blood involvement, such as anemia (low red blood cell count).
Most people diagnosed with RA who were later diagnosed with Sjögren’s syndrome had higher levels of antinuclear antibodies (ANAs) and anti-Sjögren’s antigens in their bloodstream than those who did not develop Sjögren’s syndrome. These are proteins that can allow the immune system to mistakenly attack the body. They were also more likely to experience dry mouth and dry eyes, and had higher white blood cell counts than those who did not develop Sjögren’s syndrome. Finally, they were more likely than others with RA to have taken corticosteroids to treat the condition.
Approximately half of those diagnosed with Sjögren’s syndrome have previously been diagnosed with a rheumatic condition, like RA. When this happens, it is technically referred to as secondary Sjögren’s syndrome. The exact prevalence of Sjögren’s in people diagnosed with RA is unknown. This is because Sjögren’s syndrome is difficult to diagnose and may be misdiagnosed as either RA or lupus (another autoimmune disease).
However, researchers have estimated the prevalence of Sjögren’s syndrome in those diagnosed with RA to be somewhere between 5 percent and 10 percent. Some people with RA have symptoms of Sjögren’s syndrome, although they don’t qualify for the full diagnosis. In addition, at least 50 percent of those diagnosed with Sjögren’s have joint pain, even if they do not have any type of arthritis.
Some of the blood tests run for Sjögren’s syndrome are the same as those for RA. For instance, doctors may look at the number of ANAs in your blood or look for the presence of rheumatoid factors. These often indicate RA or lupus but, in some cases, can also indicate Sjögren’s. However, most rheumatologists will not consider a diagnosis of Sjögren’s syndrome first unless there are very clear symptoms of the condition.
In addition, some of the symptoms of Sjögren’s syndrome overlap with those of RA. For instance, Sjögren’s syndrome can cause joint pain (even without arthritis), skin rashes, joint stiffness and swelling, and fatigue — all of which can also occur with RA.
Although more research is needed to fully understand the relationship between RA and Sjögren’s syndrome, scientists have identified some key aspects of living with both conditions simultaneously.
People with both RA and Sjögren’s syndrome are more likely to experience severe arthritis. However, they may be less likely to experience a fever, low platelet counts, an underperforming thyroid, or a rash. They may have more complications from the diseases and experience them throughout the body (systemic disease), rather than localized to specific joints or dry areas. People with RA and Sjögren’s syndrome are also less likely to achieve remission of either condition.
If you have been diagnosed with RA and suspect you may also have Sjögren’s, talk to your rheumatologist. They should be very familiar with both conditions and should be able to help you distinguish between the two.
Your doctor will likely start by talking to you about your symptoms. They will likely ask you specifically about dryness in your mouth and eyes. They are also likely to run Sjögren’s-specific blood tests, such as those that detect anti-SSA or anti-SSB in your blood. These are autoantibodies that can set up the immune system to attack the body.
If you have several symptoms or severe symptoms and your blood work suggests that Sjögren’s syndrome is possible, your doctor may be comfortable enough to diagnose on that basis. However, in the end, you may need to have a salivary gland biopsy to make a certain diagnosis. Your doctor will look at the biopsy for changes in line with Sjögren’s, as these would not be caused by RA.
Many of the treatments for RA and Sjögren’s syndrome overlap because they are both rheumatic conditions. These include biologics and disease-modifying antirheumatic drugs. However, adding a diagnosis of Sjögren’s may necessitate adding new treatments on top of your RA treatment regimen.
Your doctor may choose to add Sjögren’s-specific treatments to your treatment plan. These may involve treating your eyes or your salivary glands specifically, so you can avoid dryness and some of the other potential complications of Sjögren’s syndrome. You may also be referred to a specialist, such as an ophthalmologist. They can prescribe or recommend eye drops or artificial tears to hydrate the eyes and protect your cornea from dryness if you have decreased natural tear production. Your doctor may also prescribe medication to increase saliva production.
Make sure that every health care provider you see knows that you have been diagnosed with both conditions. This information can ensure that your overall treatment plan is appropriate and that you have the best chance at an improved quality of life.
Have you been diagnosed with both Sjögren’s syndrome and rheumatoid arthritis? Are you living with RA and concerned about developing Sjögren’s? Consider joining myRAteam today. On myRAteam, the social network for people with rheumatoid arthritis and their loved ones, more than 194,000 members come together to ask questions, give advice, and share their stories with others who understand life with RA.
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