Although children don’t typically fall seriously ill from the new coronavirus, doctors in Europe are now expressing concern that children with COVID-19 have developed mysterious symptoms that mimic those appearing with Kawasaki disease.

Dr. Michael Portman, pediatric cardiologist and director of the Kawasaki Disease Clinic at Seattle Children’s Hospital, helps break this emerging issue down for parents and caregivers.

Q: What is Kawasaki disease?

A: Kawasaki disease is an autoimmune response that causes inflammation in arteries. The arteries supplying the heart are particularly susceptible to this inflammation. They can form large sacs called aneurysms, which then can form clots, block blood flow, and cause irreversible and devastating damage to the heart.

Q: Who generally gets Kawasaki disease?

A: Prior to the COVID-19 pandemic, Kawasaki disease affects about 7,000 children in the U.S. each year. It develops during childhood and although it can occur in children of all ages, it most often affects young children under age 5.

Q: What are the symptoms?

A: Diagnosing Kawasaki disease can be challenging because the symptoms – which can include fever, a rash, swollen hands and feet, red eyes, swollen lymph nodes and red, swollen or cracked lips, mouth, throat and tongue – are unspecific and inconsistent. Often the most pronounced symptom is a very high fever between 101 and 104 degrees Fahrenheit that lasts for four or five days.

Q: What should parents do if they see these symptoms in their child?

A: Since the symptoms of Kawasaki disease overlap with those of COVID-19, parents should seek out the advice of a pediatrician for any fever that persists for five days. Although the fever may come and go, it’s important that the child is evaluated promptly by a health care provider familiar with Kawasaki Disease. Evaluation and treatment should not be delayed, especially during the current COVID-19 pandemic.

When treated early in the hospital, most children with Kawasaki disease can fully recover in a matter of days. If left untreated for about 10 or more days, Kawasaki disease can cause serious complications, including life-long aneurysms, stent placement, heart transplant, skin disorders and childhood anxiety. It is the most common cause of acquired permanent heart disease in children.

Q: Why might Kawasaki disease be showing up in children with COVID-19?

A: Kawasaki disease is a puzzling illness, and there is currently no known cause. We believe that a virus or bacteria triggers inflammation and an immune system overreaction. We do not know yet if the coronavirus produces a similar immune response in children. Adults with the coronavirus often show a massive immune response, which is in some ways is similar to that occurring in children with Kawasaki disease. Scattered reports in the media and among Kawasaki disease specialists suggest that some children are showing symptoms of this type of immune response when exposed to the coronavirus.

Q: What are researchers doing to better understand this condition in COVID-19 patients?

A: At Seattle Children’s we are planning studies which will monitor COVID-19 related antibody development in children with Kawasaki-like symptoms. These studies will enable us to understand how a virus triggers the immune response in children with COVID-19, Kawasaki disease or both.

Originally published on Seattle Children's On the Pulse.