The actress Christina Applegate, who received a multiple sclerosis diagnosis in 2021, said on Tuesday that she had been unexpectedly plunged back into uncertainty after a doctor told her she didn’t have multiple sclerosis, after all.
“This may come as great news, but to me it comes as like I’m back at square one,” Ms. Applegate said on “MeSsy,” the podcast she hosts with fellow actress Jamie-Lynn Sigler. “But — whew, it’s hard to say.”
She broke into tears as she described the doctor’s words. “She came into my room and she said: ‘Congratulations, you don’t have M.S. Congratulations.’”
“Well, I was not happy at all. Everybody else was so happy,” she said, adding that her symptoms did not go away when the diagnosis did. “You don’t get misdiagnosed and then all of a sudden I’m better.”
Ms. Applegate has been open for years about her illness, which she said on her podcast began with numbness in her toes that spread up her legs and advanced into pain. It took several years for her to receive a diagnosis of multiple sclerosis — a common experience with M.S. and many other diseases involving the immune system.
In multiple sclerosis, the immune system attacks the myelin sheath that surrounds nerves, causing progressive damage. The symptoms — which often wax and wane, with flares and periods of remission — can include numbness and tingling, weakness, difficulty walking, fatigue and blurred vision, among others.
Treatment can reduce symptoms and slow the disease’s progression, but there is no cure.
As with many chronic diseases, diagnosing M.S. is difficult because no single test can conclusively identify it, and many conditions can cause similar symptoms, said Bruce Bebo, the chief research and medical affairs officer at the National Multiple Sclerosis Society.
Ms. Applegate was initially diagnosed after imaging showed lesions in parts of her brain and a spinal tap revealed markers called oligoclonal bands, which signal inflammation in the central nervous system. Those findings are characteristic of M.S., but Dr. Marwa Kaisey, a neurologist at Cedars-Sinai in Los Angeles, said on the “MeSsy” podcast that they can also be found in other conditions.
Dr. Bebo noted that the standard diagnostic guidelines for multiple sclerosis were updated in 2024. One of the changes reflects new technology that can more accurately distinguish between lesions caused by M.S. and lesions caused by other diseases.