Selena Gomez announced on Instagram that she underwent a kidney transplant over the summer, and that her good friend Francia Raisa was her donor. The 25-year-old singer revealed in 2015 that she had received treatment for lupus, and she said today that the transplant had to happen because of her disease.

“It was what I needed to do for my overall health,” Gomez posted, along with photos from her hospital bed and of her transplant scar. She added: “Lupus continues to be very misunderstood but progress is being made.”

To learn more about lupus and why complications from this chronic illness can lead to kidney failure, Health spoke with physicians who have treated others with the condition. Here are six lupus facts you should know.

Lupus can affect the entire body

About 1.5 million Americans have lupus, an autoimmune disease that causes the body to attack its own tissues. “Instead of the immune system fighting off things like infection and cancer, it turns against the individual and starts acting on their own organs,” says Dr. Gary Gilkeson, professor of medicine at the Medical University of South Carolina.

For about half of those with systemic lupus erythematosus—the most common type of lupus—a major organ like the kidneys, heart, lungs, or brain will be damaged by the disease. Kidneys are commonly affected, says Gilkeson, because autoimmune proteins can be deposited there. This causes inflammation and can, over time, lead to kidney failure.

Lupus symptoms vary widely

Because lupus can manifest in so many different ways and affect many different organs, symptoms can vary a lot from person to person—and this makes the condition tricky to diagnose. The most common symptoms include fatigue, joint pain, swelling, rash, and fever, but these signs may not be obvious, or they may be misdiagnosed as another condition.

There is also no lab test for lupus, so it has to be identified by first ruling out other conditions. A 2015 study in the Annals of Rheumatic Diseases found that it takes nearly six years, on average, from the time people notice their first symptoms to the time they receive a correct diagnosis.

Gender and ethnicity can play a role

More than 90% of lupus cases occur in females, says Gilkeson, and the disease is more common in Hispanic and African women than in Caucasians. According to the Lupus Foundation of America, most people first develop symptoms between ages 15 and 44.

Lupus can be genetic; about 20% of people with lupus have a parent or sibling who has or will develop the disease. People with lupus are also likely to have family members with other autoimmune diseases as well.

Treatment for lupus can include pain meds and chemo

Depending on a person’s symptoms and disease severity, they may be able to manage lupus flare-ups with pain relievers and anti-inflammatory medicines. Others will need immunosuppressant drugs or even chemotherapy to treat the condition.

Complications from lupus may also need to be addressed, like transplants for damaged kidneys. There is no cure for lupus, but the disease can go into remission—meaning that a patient no longer experiences symptoms. With the right treatment, 80 to 90% of those diagnosed can expect to live a normal lifespan.

A kidney transplant can be good news

Even though lupus can damage the kidneys, doctors won’t typically perform a transplant until a patient is in remission, says Dr. Robert Montgomery, director of the Transplant Institute at NYU Langone Health; otherwise, the active disease would continue attacking the new kidney just like it did the old one.

When a person’s lupus is under control, however, the majority of kidney transplants are a success—especially those with live donors. The patient takes immunosuppressant drugs that not only protect the new organ from future attacks, but also helps keep lupus in remission overall.

Transplant recovery tends to be quick

It usually takes about six weeks for a kidney-transplant recipient’s incision to fully heal and for the person to get back to heir normal activity. (In one Instagram photo, a substantial scar stretches across Gomez’s lower right abdomen.) Donors typically have it a little easier, says Montgomery: Their kidney is often removed laparoscopically (with very tiny tools), which involves about a 3-inch incision near the bikini line.

For someone in Gomez’s situation, prognosis is generally very good, says Gilkeson. “She can lead a normal life after this,” he says. “Have children, do whatever she wants. She will be on medicine that suppresses her immune system, so she’s more susceptible to infection—but common sense precautions are all that are needed.”

This article originally appeared on Health.com

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