Lupus 'attacking my kidneys,' Cannon says

Celebrity Nick Cannon revealed Monday that he has an autoimmune disease called lupus nephritis.

“It’s a rare form of lupus that’s just attacking my kidneys,” Cannon told ABC’s "Good Morning America."  “They thought it was just kidney disease, and then they were trying to figure out why my immune system was attacking my kidneys, and that was sort of the root of it all.”

Like many autoimmune diseases, lupus is a mystifying condition. It's often hard to diagnose because of its vague and varying symptoms. It can affect any part of your body such as joints, skin, kidneys, heart, lungs, blood or brain.

Cannon, husband to singer Mariah Carey, has been hospitalized twice this year, once for kidney issues and a second time when doctors found blood clots in his lungs. His physicians have warned him to slow down, and Cannon announced he was stepping down from his morning radio show to prioritize his health in February.

Doctors have told the multi-tasking media personality that the blood clots were connected to his kidney problems. The majority of lupus patients have other symptoms such as arthritis, skin rash, hair loss or mouth ulcers.

Lupus nephritis causes inflammation in the kidneys, which makes them unable to properly remove waste from the blood or control the amount of fluids, according to the Lupus Foundation.

About 50 to 60% of lupus patients develop kidney problems, said Dr. Gary S. Gilkeson, associate dean and professor of medicine in microbiology and immunology at the Medical University of South Carolina. He is not involved in Cannon’s care. The kidney problems can range from mild to severe to end-stage renal disease.

African Americans as a whole develop more lupus nephritis than Caucasians and they’re more likely to develop end stage renal disease given the same treatment as people who are not African American.

Doctors believe lupus has a genetic component.

What makes Cannon’s case unusual is lupus tends to affect predominantly women. When men get lupus, it tends to be more severe, said Gilkeson, chair of the Lupus Foundation of America’s Medical-Scientific Advisory Council.

Science has no clear answers to why male cases of lupus are more difficult to treat. “It may have something to do with hormones for a man to get lupus,” he said.  “There’s a thought that it must have more of a genetic risk.”

Cannon told ABC that he “can’t have any fast food anymore.”

“Anytime you have a kidney disease, you have to watch your salt intake and your protein intake, so fast foods are very high in both of those,” Gilkeson said.  “Like anyone else, it’s better to eat healthy. You have to be more careful when you have renal involvement.”

Patients with lupus can expect to have a normal lifespan as long as they continue to receive proper treatment. The U.S. Food and Drug Administration approved a drug Benlysta (belimumab) for lupus last year.

"We hate it that someone developed the disease but appreciate him being open about it so other people can learn about it," Gilkeson said.