This blog was originally posted in 2020. Some information may be out of date. For the latest updates on vaccines, testing, screening, visitor policy and post-COVID support, visit EEHealth.org/coronavirus.

As if there wasn’t enough for parents to worry about during this pandemic, a mysterious illness has surfaced in some children.

Multisystem inflammatory syndrome in children (MIS-C) is a rare but dangerous illness in children associated with COVID-19. According to the Centers for Disease Control and Prevention (CDC), in MIS-C, different body parts become inflamed, including the heart, lungs, kidneys, brain, skin, eyes or gastrointestinal organs. 

Some experts believe MIS-C is a post-viral syndrome, or an overreaction by the body’s immune system to COVID-19. Many children affected either had exposure to someone with COVID-19, tested positive for COVID-19 or had positive antibody tests, meaning their immune system had created antibodies in response to the virus.

Preliminary data shows most of the cases are in children between ages 5 and 14 years old.

MIS-C shares some traits with toxic shock syndrome and Kawasaki disease, including persistent fever, rashes, red eyes, lips and tongue, and swollen hands and feet.

Kawasaki disease is a rare, non-contagious childhood illness that mainly affects children age 5 and younger, more commonly boys than girls. If left untreated Kawasaki disease can lead to serious heart problems, but with treatment most children fully recover within a few weeks.

Although it produces similar symptoms, MIS-C doesn’t act exactly like Kawasaki disease. MIS-C seems to affect the heart differently and more often results in features consistent with toxic shock.

Although much is still unknown about the relationship of this new syndrome to COVID-19, for now, parents should be aware of the warning signs.

The CDC provides a case definition for MIS-C. 

Symptoms of MIS-C are reported to show up several weeks to a month after exposure to the virus, and generally don’t include the typical respiratory symptoms associated with COVID-19.

Be on the lookout for the following symptoms in your child (and act quickly if you notice them):

• Persistent, prolonged high fever (4 days or more)
• Lethargy
• Skin rash or discoloration (pale, patchy or blue skin)
• Red eyes, lips and tongue
• Swollen hands and feet
• No appetite, difficulty feeding in infants
• Abdominal pain, vomiting or diarrhea
• Racing heart, trouble breathing, chest pain
• Decreased urination
• Irritability, confusion

Most children with COVID-19 seem to have mild illness and serious cases remain rare among children. Though uncommon, MIS-C is still a serious complication and some children may become very sick. Prompt treatment is important and may include blood thinners, IV immunoglobulin and corticosteroids.

In the meantime, parents, it’s important to trust your instincts. You know your child best. If you notice any of the warning signs or changes in your child, act quickly. Call your child’s doctor right away or go to the hospital.

Also, if your child is due for immunizations, you should not delay the appointment unless directed by your child’s doctor. Experts highly recommend that children get the required immunizations to protect them from other serious diseases. 

The best way to prevent MIS-C is to take actions to protect yourself from getting COVID-19, including COVID-19 vaccination. Edward-Elmhurst Health has COVID-19 vaccine appointments available to ages 5 and older, including booster doses for ages 12 and older. Schedule your COVID-19 vaccine now.

Edward Elmhurst Health is working with the pediatric infectious disease teams at Comer Children’s Hospital and University of Chicago Medicine to ensure that the children in our area receive the best care possible. Read more about our children’s services.

Read the CDC’s FAQs about children and COVID-19.

Get the latest information on coronavirus from Edward-Elmhurst Health.

Get more information about coronavirus from Healthy Driven Chicago.

The information in this article may change at any time due to the changing landscape of this pandemic. Read the latest on COVID-19.