Since 2015, actress and singer Selena Gomez has been open about her lupus battle, which got so bad that she even needed a kidney transplant. But recently, she shared an update that lupus has also caused her to develop arthritis.

Lupus is an autoimmune disease that can be hard to diagnose since many of the symptoms can also be symptoms of other diseases. Some of the symptoms include things like fatigue, weight loss, stiffness, joint pain, brain fog and headaches.

Gomez’s battle with lupus was so bad that she had to take a break from her career in 2013 in order to focus on her health battle. Despite chemotherapy and a kidney transplant, her lupus battle is not over. While she is doing much better, arthritis is one of her more recent side effects.

Arthritis is often thought of as something older people battle, but lupus arthritis is different since lupus generally impact women between the ages of 15 and 45 years old.

Rheumatologist Dr. Adam Kreitenberg told Fox News Digital, “The arthritis of lupus can be quite disabling when inadequately treated.”

The Lupus Foundation of America website, “Lupus is quite different than any other illness that causes arthritis. It should not be lumped in with these other causes of arthritis, because the causes and the treatments are very different.” The foundation explains, “After a long time of uncontrolled lupus, however, people can have damage in the joints, which causes problems even when the lupus is not flaring.”

Watch the video below to learn more about lupus and Gomez’s battle to fight this autoimmune disease.