MIS-C in Children: A Post-COVID-19 Condition

By Dr. Tuangporn Turongsomboon,

Pediatric Infectious Disease Specialist

MIS-C in Children: A Post-COVID-19 Inflammatory Syndrome

     Although children are generally less likely to contract COVID-19 or tend to exhibit milder symptoms compared to adults or the elderly, many children have been observed to develop a condition involving widespread inflammation after recovery. Medically, this is referred to as Multisystem Inflammatory Syndrome in Children (MIS-C).

Symptoms of MIS-C in Children

     MIS-C is a condition in which inflammation occurs in various organs of the body following a COVID-19 infection. It is believed to result from an abnormal immune response. Symptoms may resemble those of Kawasaki disease, such as high fever, rash, red eyes, and red lips. In severe cases, hospitalization in an intensive care unit may be required, and there is a risk of serious complications, including death.

Cause of MIS-C

     MIS-C is caused by an abnormal immune response to a prior COVID-19 infection, leading to inflammation in multiple organ systems. It typically manifests either toward the end of the acute infection or within 2–6 weeks after recovery.

Organs Affected by MIS-C

     MIS-C primarily affects the cardiovascular system, though it can also impact several systems simultaneously. For example, it may involve the skin and mucous membranes, resulting in rashes, or the gastrointestinal tract, causing symptoms such as abdominal pain, vomiting, or diarrhea.

Does MIS-C Affect the Respiratory System?

     While MIS-C may impact the respiratory system, this is relatively uncommon. It differs from COVID-19, which primarily targets the respiratory tract. Most MIS-C patients do not present with symptoms such as coughing, sneezing, or nasal congestion, but may experience shortness of breath due to heart involvement.

Progression of MIS-C: Early, Middle, and Late Stages

     In the early stages, some children may present with symptoms such as fever, vomiting, or diarrhea, potentially leading to a misdiagnosis of gastrointestinal infection. The condition tends to progress rapidly, usually within one week, leading to multisystem involvement such as rashes, red eyes, breathing difficulties, or, in some cases, shock.

How is MIS-C Different from Kawasaki Disease?

     Although MIS-C and Kawasaki disease share similar characteristics, they have key differences. Kawasaki disease typically occurs in children under the age of five, while MIS-C is more commonly seen in children aged 8 to 11 years. MIS-C patients more frequently exhibit gastrointestinal symptoms and abnormal heart function and are at a higher risk of shock. If symptoms arise, it is essential to consult a physician for a proper diagnosis through blood tests and echocardiography to distinguish between the two conditions.

Is MIS-C an Infectious Disease?

     MIS-C is not a contagious disease. It is not caused by a direct viral infection but rather by an abnormal immune response following exposure to COVID-19.

What Are the Risk Factors for MIS-C?

     Currently, the only clearly identified risk factor is a previous COVID-19 infection or close contact with an infected individual. MIS-C is reported more frequently in boys than in girls.

Recommendations for Parents

     If your child has recovered from COVID-19, it is important to closely monitor for any unusual symptoms. If any abnormalities are observed, seek medical attention immediately for diagnosis and appropriate treatment.