By Steven Reinberg, HealthDay Reporter

FRIDAY, Sept. 15, 2017 (HealthDay News) -- When pop star Selena Gomez revealed that she had a kidney transplant, she put the autoimmune disease lupus in the spotlight.

Lupus turns the body's immune system against itself and attacks vital organs, including the kidneys, which is why it's so devastating. But little is known about what causes the disease, and no real cure exists. Treatments can only keep it at bay.

"Selena has a lot of courage to speak out about her condition and call attention to lupus," said Dr. Anca Askanase. She is clinical director of the Lupus Center at Columbia University Medical Center in New York City.

Because Gomez needed a transplant at age 25, she probably developed lupus at an early age, added Askanase, who is also a spokeswoman for the Lupus Research Alliance.

The superstar singer first told Billboard in 2015 that she had been diagnosed with lupus and was undergoing chemotherapy. A year later, she took a career break and told People magazine at the time:

"I've discovered that anxiety, panic attacks and depression can be side effects of lupus, which can present their own challenges," Gomez said. "I want to be proactive and focus on maintaining my health and happiness, and have decided that the best way forward is to take some time off."

Gomez took more time off from her career last summer and emerged with an Instagram photo revealing she had had the kidney transplant and was now recovering. Alongside her in the photo was the donor, actress Francia Raisa, a longtime friend.

"There aren't words to describe how I can possibly thank my beautiful friend Francia Raisa," said Gomez. "She gave me the ultimate gift and sacrifice by donating her kidney to me. I am incredibly blessed."

Askanase said that half of all lupus patients develop kidney problems, but in younger patients, it's about 70 percent.

Of those who have kidney damage, about 10 percent to 15 percent end up needing dialysis or a transplant, she added.

"A large percentage of lupus patients do very well with a transplant, and part of that is because the medications used to prevent rejection are the same medications used to treat lupus," Askanase said.

"There is a 50/50 chance of making things better and a 20 percent chance of putting the disease in remission," she noted.

"We are still trying to understand which patients are going to have good outcomes and those who aren't," Askanase said. "And lupus still carries a risk of death."

No one really knows how common lupus is, but what is known is that it is more common among women than men, and more common among blacks and Hispanics than whites, Askanase noted.

"It's a disease of young women," she said. "The peak time of diagnosis is between 15 and 34. The younger you are when you get lupus, the more aggressive the disease is."

Although it's not known what causes lupus, those who get it clearly are genetically disposed to it, Askanase added.

"There is also an environmental trigger, which can include infections like the Epstein-Barr virus," Askanase explained. "In addition, smoking may be a trigger."

Lupus can attack any part of the body -- the skin, the joints, the kidneys, the brain and the heart. "That's the thing that's so devastating about lupus," she said.

And it takes years to develop, Askanase said.

Often the first symptoms are vague and may include joint pain, stiffness and swelling. Most patients also experience debilitating fatigue.

"It's beyond being tired. It's overwhelming, almost an inability to function," she said. "About 50 percent of patients also develop skin rashes."

Treatment for lupus includes the malaria drug hydroxychloroquine, which helps reset the immune system. Treatment also includes steroids to fight the inflammation associated with the disease, as well as some immune-suppressant drugs and chemotherapy drugs. In 2011, the U.S. Food and Drug Administration approved belimumab, the first so-called biologic drug to fight lupus.

Lupus ranges from mild to severe. "Mild lupus may only show up as a skin rash," Askanase said.

According to Dr. Len Horovitz, an internist at Lenox Hill Hospital in New York City, for some patients the signs of lupus can come and go.

"Patients with mild lupus can go into remission for long periods -- often for 10 years or more," he said.

Dr. Diane Kamen, director of clinical research in the rheumatology division at the Medical University of South Carolina in Charleston, said, "It's not easy for anybody living with lupus."

Once the inflammation has turned into scarring and damage is already done, it's very difficult to manage because it is no longer really treatable, said Kamen, who is a spokeswoman for the Lupus Foundation of America.

And she noted, lupus is an unpredictable condition that can flare at inopportune times.

"You can do everything right and you can still have a lupus flare that ends up with you in the doctor's office or in the hospital," Kamen said.

SOURCES: Anca Askanase, M.D., M.P.H., assistant professor, medicine, clinical director, Lupus Center, Columbia University Medical Center, New York City, spokeswoman, Lupus Research Alliance; Diane Kamen, M.D., associate professor medicine, director, clinical research, division of rheumatology, Medical University of South Carolina, Charleston, spokeswoman, Lupus Foundation of America; Len Horovitz, M.D., internist, Lenox Hill Hospital, New York City

Note: This article was published more than one year ago. The facts and conclusions presented may have since changed and may no longer be accurate.

Copyright © 2017 All rights reserved.

Here are some question-and-answer threads from MyLupusTeam:

• Does anyone have kidney and lung involvement?

• How do I hide the ammonia odor from kidney disease?

• To share or not to share? I've been learning so much about HOW misunderstood lupus is, how LITTLE the public knows about it...so that's what got me thinking, why NOT shout it from the rooftops?

Here are some conversations from MyLupusTeam:

• "I was in the hospital for 3 weeks and during that time, lupus also attacked my kidneys. So the diagnosis was lupus nephritis, also with having antiphospholipid syndrome."

• "Because of lupus I am stage 3 kidney disease with a half of a kidney, but that is ok, and pain all over my body some days I can't even get out of bed..."

• "My kidneys dropped to 5% functioning and they are ready to put me on dialysis."

What do you think about celebrities like Gomez publically sharing their personal struggles about living with a chronic illness like lupus? Share in the comments below or directly on MyLupusTeam.