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What Is Multi-System Inflammatory Syndrome? Experts Explain

With all this COVID-19 pandemic stuff happening right now, the universe decided that we needed something else to worry about, I guess. A new phrase is popping up in headlines — multi-system inflammatory syndrome — and it apparently affects kids. Ugh, I just don’t think I can handle any more, guys. Does this also have to do with COVID or is this its own separate condition that’s starting to make kids sick? Should we be worried?

Multi-system inflammatory syndrome — or MIS-C — is a serious health condition that occurs in children under 21 years of age, and according to the American Academy of Pediatrics (AAP), "The Centers for Disease Control and Prevention (CDC) has made a connection between COVID-19 and MIS-C. While we do not know who is most at risk for this illness, scientists around the world are working hard to understand this syndrome and how best to treat it." ​

Dr. Robert Hamilton, a pediatrician at Providence Saint John’s Health Center in Santa Monica, California, tells Romper, “The most important thing that parents should know is first, MIS-C is very, very rare and only occurs in children who have had COVID. Another important point that parents should understand is MIS-C is treatable, and that children who get this late complication of COVID recover.”

Dr. Daniel Ganjian, who is also a pediatrician at Providence Saint John’s Health Center in Santa Monica, California, tells Romper that thankfully, not all young patients with COVID get this syndrome. "In fact it is very rare to get it. It is a complication of COVID that affects the sickest kids. Multiple organ systems are affected (cardiac, renal, respiratory, hematologic, gastrointestinal, dermatologic or neurological).”

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So what does this look like exactly? “It is manifested in children as an unexplained fever for four to five days, red eyes without discharge, a red tongue, red and cracked lips, body rashes, swollen lymph nodes, swollen hands and feet, stomach pain, and aneurysms," Hamilton says. These aneurysms are caused by the coronary arteries becoming dilated due to the organ systems being affected. Hamilton adds it’s similar to “Kawasaki Disease" (KD), which was first described in Japan. Though KD was thought to have been caused by a virus and that there was a “genetic predisposition to the condition,” Hamilton notes.

The AAP says that another symptom that's been noted in children who have MIS-C is confusion, or seeming overly sleepy.

“With the advent of COVID, researchers in the United Kingdom noted an increase in previously healthy children who were presenting with a ‘Kawasaki-like’ syndrome. When these patients were checked for COVID infection, many were found to have antibodies to the coronavirus, indicating that they had previously been infected with COVID,” Hamilton says. “The thinking among researchers is this newly defined syndrome is a late complication in some children who have been infected with COVID.”

However, Ganjian reiterates that parents shouldn’t feel that just because their kids have had COVID doesn’t mean they’ll develop this syndrome — rather, a vast majority will not.

“Like any disease, there are cases of children who have died from it, but most recover, especially with our therapies: IVIG, and sometimes, steroids. Most recover over months,” Ganjian says.

“There have been a handful of deaths due to MIS-C, but they have been extremely rare,” Hamilton adds.

Ganjian says to be sure to speak to your doctor if you feel your child has some of the symptoms — fever, rash, stomachache, diarrhea, COVID, or any other concerns.


Dr. Robert Hamilton, pediatrician at Providence Saint John’s Health Center in Santa Monica, California, and host of the podcast ‘The Hamilton Review: Where Kids and Culture Collide’

Dr. Daniel Ganjian, pediatrician at Providence Saint John’s Health Center in Santa Monica, California