Multisystem inflammatory syndrome in children (MIS-C), though uncommon, is a serious illness that can occur following a COVID-19 infection. Children who have had COVID-19 should be monitored for any reactions that may be symptoms of MIS-C.
Because not much is currently known about the syndrome, it’s important to report and treat symptoms immediately, both to protect the child from complications and to help providers better understand MIS-C and implement better responses.
What is MIS-C?
MIS-C is an inflammatory reaction in the body occurring between two and six weeks after COVID-19 infection. The inflammation can affect the heart, lungs, blood vessels, kidneys, digestive system, brain, skin and eyes. MIS-C, also called pediatric inflammatory multisystem syndrome (PIMS) has features in common with toxic shock syndrome and Kawasaki disease, both of which cause inflammation throughout the body.
Though the syndrome mostly affects school-age children, predominantly 8- and 9-year-olds, it has also been seen in infants and young adults. Multisystem inflammatory syndrome in adults (MIS-A) occurs in adults who were previously infected with the COVID-19 virus. It can occur during a COVID-19 infection or appear a few weeks after infection.
MIS-C is triggered by the virus that causes COVID-19, with symptoms appearing between two and six weeks. Most children with MIS-C have antibodies to the virus, indicating a previous infection. Children may have MIS-C even if they did not experience symptoms associated with COVID-19.
The number of MIS-C cases typically rise about four weeks after waves of COVID-19 cases in communities. However, not all children who had COVID-19 develop MIS-C; doctors are still unsure why.
Symptoms of MIS-C can overlap with infections and other illnesses, and not all children experience the same symptoms. Initial symptoms include:
- Red eyes.
- Stomach pain.
- Rapid breathing or heartbeat.
- Redness or swelling of the lips, tongue, hands or feet.
- Headache, dizziness or lightheadedness.
- Enlarged lymph nodes.
MIS-C is rare and treatable, but dangerous, and can worsen each day to the point where lives are at risk. Because of this, it’s important to immediately contact a provider if any symptoms are present, especially emergency warning signs.
Emergency symptoms include:
- Severe stomach pain.
- Difficulty breathing.
- Pale, gray or blue-colored skin, lips or nail beds – depending on skin tone.
- New confusion.
- Inability to wake up or stay awake.
Call a doctor immediately if a child experiences any of the emergency symptoms listed above, or has a persistent fever of 100.4 accompanied by any other symptoms.
MIS-C is treatable and most children recover fully. Intravenous immunoglobulin, steroids and other anti-inflammatory medicines can reduce the inflammation and protect the body from lasting damage. However, swift action is necessary to avoid complications and death. Parents with children who have had COVID-19 and continue to experience a fever or other symptoms should contact a pediatrician immediately.
Even if children aren’t severely ill, they should still see a doctor if they are experiencing any symptoms of MIS-C. Doctors may want to test the blood, chest, heart or abdomen to check for inflammation and other signs of MIS-C that may not be obvious.
Because not much is known about the syndrome, testing for any symptoms of MIS-C regardless of severity can help better inform providers. The Centers for Disease Control and Prevention (CDC) and the National Institutes of Health are working with providers nationwide to share data, learn more about risk factors and improve diagnosis and treatment.