Lupus and Arthritis: What's the Connection?
The Connection Between Lupus and Arthritis
Lupus and arthritis are often confused because they have similar symptoms. To make things even more confusing, many people who have lupus also develop arthritis—and vice versa.
When a person has two independent diseases, it’s called comorbidity. According to one article, the lupus/arthritis comorbidity might be based in genetics.
Just one gene in your body can cause both lupus and arthritis.
What Is Lupus?
Lupus is an autoimmune disease that attacks joints and internal organs, including the heart and kidneys. People with lupus often have rashes across the face. Their rashes might worsen with sun exposure.
Lupus can cause more serious issues, such as seizures. Some people with lupus also have low red or white blood cell counts. When your white blood cell count is low, your immune system weakens. That leaves you exposed to infections and diseases.
What Is Arthritis?
Arthritis mostly affects the joints. It can cause everything from simple morning stiffness to painful swelling and pain. According to a CDC report, 25.6 percent of people with arthritis suffer severe pain, and 37.7 percent say it affects their daily activities.
Arthritis often causes the joints to look red and swollen. If you have arthritis, your joints might have a shorter range of motion. This means you can’t extend your joints all the way without pain or discomfort.
The Genetic Link
A 2007 study showed a genetic link between lupus and rheumatoid arthritis. That link has to do with mutations of the gene “STAT4.”
People who carry a mutated version of this gene have twice the risk of developing lupus. They also have a 60 percent higher risk of developing rheumatoid arthritis.
The connection between the two diseases is so strong that doctors use the term “lupus arthritis” to refer to arthritis that occurs in lupus patients.
Gene STAT4 Mutations
Scientists don’t know what causes gene STAT4 to mutate. They do know that when it happens, the risk of developing autoimmune disorders increases.
According to the U.S. National Library of Medicine’s Genetics Home Reference, mutations of gene STAT4 also increase the risk of juvenile idiopathic arthritis and systemic scleroderma, a disease that leads to the excessive buildup of scar tissue.
What Does It All Mean?
Unfortunately, there’s no easy way to know whether you carry a variant of STAT4. Genetic testing is still in its infancy, and it might take decades before scientists develop accurate tests that are available to the public.
So far, all the research involving the STAT4 gene has been done at universities or medical centers. These studies are paving the way to learning how genes and autoimmune diseases are connected. One day, they might also lead to new, more effective forms of treatment.
What Can Be Done?
The genetic connection between lupus and arthritis means that both diseases could respond to similar treatments. Depending on your symptoms, you might need to combine a number of treatments to help you control flare ups and reduce organ damage.
Both arthritis and lupus might require drugs to help prevent damage to the joints and reduce painful swelling. A physical therapist can also help you learn some basic stretches and exercises to ease joint stiffness.
The Good News
According to the Lupus Foundation of America, lupus arthritis causes less destruction of the joints than rheumatoid arthritis. In fact, joint deformities appear in less than 10 percent of people diagnosed with this form of arthritis.
More good news is that other symptoms, like stiffness and inflammation, are often stronger in the morning and wear off throughout the day.
- Differences in the Prevalence and Impact of Arthritis Among Racial/Ethnic Groups in the United States, National Health Interview Survey (2010, May). Center for Disease Control and Prevention. Retrieved October 1, 2013, from http://www.cdc.gov/pcd/issues/2010/may/10_0035.htm
- Elaine F. Remmers, Ph.D. et al. (2007, December). STAT4 and the Risk of Rheumatoid Arthritis and Systemic Lupus Erythematosus. The New England Journal of Medicine, 10.1056, 357:977-986. Retrieved October 1, 2013, from http://www.nejm.org/doi/full/10.1056/NEJMoa073003
- Genetic Testing and Screening in the Age of Genomic Medicine (2011, January). New York State Department of Health. Retrieved October 1, 2013, from http://www.health.ny.gov/regulations/task_force/reports_publications/screening.htm
- Sherine E Gabriel et al. (2009). Epidemiological studies in incidence, prevalence, mortality, and comorbidity of the rheumatic diseases. Arthritis Research and Therapy, 11(3):229. Retrieved October 1, 2013, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2714099/?tool=pubmed
- STAT4. (2013, September 23). Genetics Home Reference. Retrieved October 1, 2013, from http://ghr.nlm.nih.gov/gene/STAT4
- What Is Lupus? Fast Facts: An Easy-to-Read Series of Publications for the Public (2009, October). National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS). Retrieved October 1, 2013, from http://www.niams.nih.gov/Health_Info/Lupus/lupus_ff.asp#f
- How Does Lupus Affect the Musculoskeletal System? (2013, July 12). Lupus Foundation of America. Retrieved October 1, 2013, from http://ghr.nlm.nih.gov/gene/STAT4