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Today, the Sjögren’s Foundation recognizes patients with rare diseases and their representative health organizations as we celebrate Rare Disease Day, which is held on the rarest day of the year— February 29th (and February 28th, during non-leap years). Since we are celebrating, you may be asking yourself “Is Sjögren’s a rare disease?” The simple answer is no, but other factors make this answer more complicated. 

A rare disease is defined as having a prevalence of 1 in 2,000 (<200, 000) people and there are over 300 million people living with a rare disease worldwide.1 However, we estimate that around four million Americans have Sjögren’s— a prevalence of approximately 1 in 85.2 

So, why is Sjögren’s often misrepresented as a rare disease? 

Sjögren’s is the second most common autoimmune rheumatic disease, but lesser known than more commonly known diseases like rheumatoid arthritis and systemic lupus erythematosus. The major reason Sjögren’s is misrepresented as a rare disease is that patients are often underdiagnosed and/or misdiagnosed, especially since many autoimmune diseases have overlapping symptoms and clinical biomarkers. In a recent study from the Oklahoma Medical Research Foundation (OMRF), it was determined that 35% of patients with Sjögren’s were misdiagnosed with another autoimmune disease, while 17% had Sjögren’s that overlapped with another autoimmune disease. Approximately 55% of patients in this study did not have a prior diagnosis of an autoimmune disease, but 44% of those that were not diagnosed with an autoimmune disease were subsequently diagnosed with Sjögren’s.3 

Editor’s Note: Sjögren’s patients can also have overlapping rare diseases such as scleroderma, polymyalgia rheumatica, myositis, among others. 

Until recently, it took more than five years, on average, to obtain a Sjögren’s diagnosis after onset of symptoms. Thankfully due to the increase of awareness and advocacy efforts, the time to diagnosis, on average, after patient recognition of symptoms has decreased to less than three years. However, some symptoms may not be easily recognized by the patient as a concern; for example, a person cannot tell they have dry mouth until approximately 50% of their saliva production is gone. Furthermore, patients with Sjögren’s have a difficult time getting a diagnosis because they often present with symptoms and biomarkers that overlap with other autoimmune diseases. Another reason Sjögren’s is misrepresented as a rare diseases is that there have not been extensive epidemiological and population studies on the prevalence of Sjögren’s.

Rare diseases and Sjögren’s have some universal challenges in common:

  • There is a need for better quality information and scientific knowledge for healthcare providers to avoid a delay in diagnosis
  • Treatment and care are not always readily accessible, available, or can present with a high financial burden on patients
  • The overlap of common symptoms and heterogeneity of disease manifestation across patients contributes to underdiagnosis and misdiagnosis
  • Due to the unknown role that genetics, environment, and population play in many of these diseases, it is important to work collaboratively with all stakeholders 

To address these challenges, the Foundation continues to provide education and awareness on diagnosing Sjögren’s and the wide array of manifestations a Sjögren’s patient may present with. We also continue to support both national and international research initiatives focused on the diagnosis, prevention, and treatment of Sjögren’s. 

So, while Sjögren’s is not a rare disease, rather, it is a systemic and serious disease that is much more common than previously thought, we add our voice in support of Rare Disease Day and all of the patients and organizations represented by this important national health observance. 


  1. Rare Disease Day 2020 - 29 Feb. Rare Disease Day - 29 Feb 2020. Published February 28, 2019.
  2. Wallace DJ. The Sjögren’s Book. Fifth edition. Oxford University Press; 2022.
  3. Rasmussen A, Radfar L, Lewis D, et al. Previous diagnosis of Sjögren's Syndrome as rheumatoid arthritis or systemic lupus erythematosus. Rheumatology (Oxford). 2016;55(7):1195-1201. doi:10.1093/rheumatology/kew023