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Kawasaki Disease, Pediatric Multisystem Inflammatory Syndrome, and COVID-19 Explained

Baby with Rash on Back

Most children with COVID-19 do not become seriously ill (and many are thought to be asymptomatic). But recently, there have been reports of a new complication of the virus in children in the United States and Europe. Known as Multisystem Inflammatory Syndrome in Children (MIS-C) or Pediatric Multisystem Inflammatory Syndrome (PMIS), this rare disorder shares some features with Kawasaki disease (KD), another inflammatory condition seen in children. Doctors are working to understand this phenomenon. For now, here is what we know about these illnesses, as well as some important symptoms to look out for.

What are KD and PMIS? Are they the same thing?

KD is a type of vasculitis (an inflammation of the blood vessels) that occurs in young children. Though doctors don’t know what causes KD, many theories, including an infectious trigger, have been proposed. Children with KD have high fevers lasting at least five days, as well as symptoms including chapped lips, swollen lymph nodes, red eyes, swelling or peeling of the hands and feet and rashes. Some children with KD develop serious complications, such as inflammation of the coronary arteries, which supply blood to the heart.

In the spring of 2020, doctors began seeing pediatric patients with evidence of current or past COVID-19 infection who were sick with an inflammatory disorder that shared some features with KD. This disorder, which is now called PMIS, is thought to be caused by an overresponse of the immune system to COVID-19. Doctors are looking for evidence to understand how PMIS relates to KD; though it is not exactly the same, children may have some of the same symptoms. In addition to the above, children with PMIS may have severe abdominal pain, a sore throat, headache and signs of altered mental status. Some children with PMIS have gone into shock, in which the heart is not able to adequately pump blood to the rest of the body.

My child has or recently had COVID-19. How concerned should I be?

Doctors are still learning about how common PMIS is, but it appears to be very rare. Though many children are believed to be positive for COVID-19, only a small number of them develop symptoms of PMIS. Most children with PMIS recover quickly with adequate therapy. However, delayed treatment may result in serious or even fatal complications. Therefore, it is important to know the signs and symptoms of PMIS so your child can begin treatment immediately if necessary.

When should I call my child’s doctor or go to the ER?

Fevers in children are common, due to both COVID-19 and regular childhood diseases. If your child develops a fever or otherwise seems ill, you should call his or her pediatrician to discuss. Be sure to mention if your child has any other symptoms, including rashes, sore throat, stomachache, diarrhea, vomiting, red eyes, or swollen lymph nodes, tongue, hands or feet. Your pediatrician may tell you to go to the ER for further assessment, or may give you instructions for watching your child at home. If your child has signs of dehydration (e.g., dry cracked lips, abnormal tear production), altered mental status (e.g., confusion, lethargy) or difficulty breathing, call 911 or go to the ER right away.

How can I prevent my child from developing PMIS?

The best way to prevent PMIS is to prevent the spread of coronavirus. Social distancing, handwashing, avoiding visibly sick people and isolating sick family members are all important practices for keeping your family safe. Right now, there is no known way to decrease the risk of PMIS in a child who has had COVID-19. As doctors understand more about the cause of this syndrome, we will learn more about the best ways to treat and prevent it.

Learn more about staying healthy during the coronavirus outbreak.

Dr. Sarah Taber, rheumatologist

Dr. Sarah Taber is a pediatric rheumatologist at HSS, and is board certified in both pediatrics and pediatric rheumatology. Dr. Taber specializes in the diagnosis and treatment of children with rheumatic diseases, including juvenile idiopathic arthritis, childhood systemic lupus, dermatomyositis, vasculitis, and systemic and localized scleroderma. She is a Consult Editor of Rheumatology for Medscape, and winner of the #1 Consult Case of the Year for 2019. Dr. Taber has also been a featured speaker for the Scleroderma Foundation, Charla de Lupus, and A Lasting Mark Foundation.

The information provided in this blog by HSS and our affiliated physicians is for general informational and educational purposes, and should not be considered medical advice for any individual problem you may have. This information is not a substitute for the professional judgment of a qualified health care provider who is familiar with the unique facts about your condition and medical history. You should always consult your health care provider prior to starting any new treatment, or terminating or changing any ongoing treatment. Every post on this blog is the opinion of the author and may not reflect the official position of HSS. Please contact us if we can be helpful in answering any questions or to arrange for a visit or consult.