Get the latest from TODAY

Sign up for our newsletter
 / Updated  / Source: TODAY
By Gabrielle Frank

When singer and actress Selena Gomez revealed she had been diagnosed with lupus two years ago, she brought high-profile attention to a relatively rare disease that affects 1.5 million people in the U.S., striking women far more often than men.

Since then, Gomez, 25, has been surprisingly open about her struggle with the disease. In September, she revealed that she'd undergone a kidney transplant over the summer as a result of her condition.

"My kidneys were done," she told TODAY in an exclusive two-part interview airing this week.

In 2014, she went through chemotherapy to treat lupus in 2014, and took a break from the spotlight in 2016 to deal with anxiety, panic attacks and depression, which can be side effects of lupus.

Earlier this month, after sharing the news of her surgery, she wrote on Instagram, "... I found out I needed to get a kidney transplant due to my Lupus... It was what I needed to do for my overall health."

Since opening up about her grueling condition, the 25-year-old actress has been praised for raising awareness of and supporting research for the autoimmune disease.

What is lupus?

Lupus can attack any part of the body including the joints, skin, kidneys and lungs.

"Some of the most common symptoms of lupus are fatigue, hair loss... sometimes women with lupus... feel it's almost too hard to get out of bed in the morning," Ken Farber, president and CEO of the Lupus Research Alliance told TODAY. "That's how severe the fatigue can be, but debilitating as those symptoms are, what we worry about are the complications for the heart, the brain and the kidney. That's what makes lupus life-threatening."

According to the Lupus Foundation of America, the disease most commonly occurs in women of childbearing age and is more likely to occur in women of color. However, men, children and teens can develop it, too.

Symptoms can also include cognitive issues, disfiguring rashes and painful joints. Some people experience no symptoms.

There are four different types of lupus: systemic, cutaneous, drug-induced and neonatal. The most common form is systemic lupus, and in nearly half of these instances a major organ or tissue in the body (heart, brain, lungs, kidneys) is affected.

What causes lupus?

Lupus is a genetic disease.

"Right now, there's no way to prevent lupus," Farber said. "What people inherit, with lupus, is not actually lupus itself, but a susceptibility to lupus. We know that there are some agents in the environment which turn on or activate the process of lupus in genetically susceptible women."

Lupus can occur in people who have no family history of the disease, but there may be cases of other autoimmune diseases within the family.

How is it diagnosed?

According to the Lupus Foundation of America, it can take nearly six years for a person to be diagnosed with the disease.

Lupus is especially difficult to diagnose because there's no simple blood test for it. And, previously, very few people had heard of it. Even doctors were unfamiliar with lupus before Selena Gomez brought so much attention to its debilitating effects.

There are a variety of tests that must be interpreted by physicians, primarily rheumatologists, according to Farber. But an accurate diagnosis can take time.

"Lupus has been a misunderstood disorder, very few people knew what it was," he said. "All of that has changed... because Selena has been brave enough to tell her story in front of the whole world."

The most distinctive lupus symptom is a butterfly rash which appears on the face, resembling the wings of a butterfly across both cheeks. Lupus can also cause fatigue, fever, joint pain and dry eyes.

People with lupus may experience their fingers turning white and or blue in the cold, which is known as Raynaud's syndrome.

How do you treat lupus?

Lupus can be life-threatening, although there are treatments that lessen the severity of the pain, including anti-inflammatory medications and immunosuppressants.

"The good news is that there are a lot of new treatments available," said Farber. "Many of these new treatments lessen the symptoms and let women with lupus live much more normal life spans."

Kidney disease is one of the most common complications of lupus, although not every patient will need a transplant or dialysis.

"What we want women with lupus to know is that the best medicine is hope, and we're in the business of providing hope — and there's a lot of reason to be optimistic," Farber said.