Overview

Multisystem inflammatory syndrome in children (MIS-C) is a group of symptoms linked to swollen, called inflamed, organs or tissues. People with MIS-C need care in the hospital.

MIS-C was first detected in April 2020. MIS-C is currently linked to coronavirus disease 2019 (COVID-19). Experts are still studying the cause of MIS-C and risk factors for getting it.

Most children who catch the COVID-19 virus have only a mild illness. But in children with MIS-C, after infection with the COVID-19 virus, the blood vessels, digestive system, skin or eyes become swollen and irritated.

MIS-C is rare. It most often happens within 2 months after having COVID-19. The child may have had a known infection. Or a close contact may have a confirmed infection.

Most children who have MIS-C eventually get better with medical care. But some kids quickly get worse. MIS-C can cause life-threatening illness or death.

Multisystem inflammatory syndrome in adults

Rarely, some adults develop symptoms similar to those of MIS-C. This is called multisystem inflammatory syndrome in adults (MIS-A).

It also is linked to a current or earlier infection with the virus that causes COVID-19. People with a prior infection may not have had serious symptoms.

Symptoms

Symptoms of multisystem inflammatory syndrome in children

The symptoms of MIS-C are serious and are treated in the hospital. Not all kids have the same symptoms. But if no other diagnosis fits, health care professionals may diagnose MIS-C if a child:

  • Either had COVID-19 or has a close contact who had COVID-19 in the 2 months before hospitalization.
  • Has a fever.
  • Has a blood test result that shows a high level of inflammation throughout the body, called systemic inflammation.
  • Has at least two of the following symptoms:
    • Heart problems.
    • Red, bloodshot eyes.
    • Redness or swelling of the lips and tongue.
    • Redness or swelling of the hands or feet.
    • Pain in the belly, vomiting or diarrhea.
    • Problems with blood clotting.
    • Shock.

Emergency warning signs of MIS-C

Get help right away if your child has:

  • Severe stomach pain.
  • Pain or a feeling of pressure in the chest.
  • Problems breathing.
  • Pale gray or blue skin, lips or nail beds.
  • New confusion.
  • Inability to wake up or stay awake.

When to see a doctor

If your child has any of the emergency warning signs listed above, or is severely sick with other symptoms, get care right away. Take your child to the nearest emergency department or call 911 or your local emergency number.

If your child isn't severely ill but shows other symptoms of MIS-C, contact your child's health care professional right away for advice.

The health care team may want to do tests to check for areas of inflammation and other signs of MIS-C. These may include blood tests, or imaging tests of the chest, heart or abdomen.

Causes

The exact cause of MIS-C is not known yet. Many children with MIS-C have had a recent infection with the COVID-19 virus. Some may have a current infection with the virus.

One idea of a possible cause of MIS-C is that infection with the virus that causes COVID-19, either current or earlier, causes the immune system to overreact.

Risk factors

Children diagnosed with MIS-C are often between the ages of 5 and 11 years old. But cases are reported among children ages 1 to 15. A few cases have also happened in older kids and in babies.

Complications

MIS-C is thought to be a complication of COVID-19. Without early diagnosis and treatment, MIS-C can lead to severe problems with vital organs, such as the heart. In rare cases, MIS-C could lead to permanent damage or even death.

Prevention

In the U.S., COVID-19 vaccines are now offered to people age 6 months and older.

A vaccine can prevent you or your child from getting or spreading the COVID-19 virus. If you or your child gets COVID-19, a COVID-19 vaccine could prevent you or your child from becoming seriously ill.

To prevent getting the COVID-19 virus and spreading it to others, the CDC recommends following these precautions:

  • Keep hands clean. Wash hands often with soap and water for at least 20 seconds. If soap and water aren't available, use a hand sanitizer that has at least 60% alcohol.
  • Avoid close contact with anyone who is sick. Avoid people who are coughing, sneezing or showing other signs that they might be sick and contagious.
  • In public indoor spaces, keep distance between yourself and others. This is especially important in places with poor airflow.
  • When COVID-19 community levels are high, wear a face mask in public indoor places. If your area has a high number of people with COVID-19 in the hospital, masks help prevent infection. The CDC suggests wearing the most protective mask possible that you'll wear regularly, fits well and is comfortable.
  • Avoid touching your nose, eyes and mouth. Urge your child to follow your lead and avoid touching the face.
  • Cover your mouth with a tissue or your elbow when you sneeze or cough. Throw away the used tissue. Wash your hands right away.
  • Clean and disinfect high-touch surfaces regularly. This includes areas of your home such as doorknobs, light switches, remotes and keyboards.
By Mayo Clinic Staff