Multisystem inflammatory syndrome in children (MIS-C) is a newly recognized illness. For many children, it seems to be a complication of COVID-19. It appears after the child has already been infected with the virus. However, not all children with symptoms of MIS-C will test positive for the virus.
Doctors believe that because COVID-19 is a new virus and a child’s immune system has not been exposed to it, the child has a delayed immune response to the coronavirus. The immune system goes into overdrive and causes inflammation. MIS-C appears to be a late effect after the virus is gone.
The inflammation causes blood vessels to become leaky. When the vessels become leaky, blood can't get to the organs. When oxygen can't get to the organs, the organs get damaged.
Clinically, MIS-C can mimic Kawasaki disease, which is an inflammation of blood vessels. Kawasaki disease has not been associated with a specific virus. In Kawasaki disease, blood vessels may increase in size or form aneurysms. This has not been reported for MIS-C. MIS-C has a range of symptoms that may include:
- Bloodshot eyes
- Rash or peeling skin
- Swollen tongue
- Swollen hands and feet
- Cracked lips
- Enlarged lymph node in the neck
Other symptoms may include:
- Stomach pain
- Swollen stomach
Call a doctor if your child has any of these symptoms. Call even if the child has not been infected with COVID-19.
Keep in mind that a pretty small number of children have developed signs and symptoms of MIS-C. Most children have also recovered quickly. While MIS-C may seem like a mysterious illness, most pediatricians are familiar with this condition. It’s a form of autoinflammatory disease. At this time, researchers aren’t sure why or how this condition appears in some children. They aren’t sure how it’s related to COVID-19.