An App that Demystifies a Killer Disease

Kawasaki disease is every parent’s nightmare. This rare illness causes inflammation in blood vessels throughout the body and is the leading cause of acquired heart disease in babies and young children. Historically, it’s been difficult to diagnose, until recently, when a young inventor developed an app that can detect it.

Ellen Xu’s invention scans a photograph of the child and looks for telltale signs of Kawasaki disease, such as rashes and a swollen tongue. It’s a brilliant innovation that likely wouldn’t have come about if it all weren’t so personal.

When Xu, a San Diego native, was 5 years old, her parents rushed her kid sister to the hospital. Three-year-old Kate had a fever, reddened eyes, a rash and swelling in her hands and tongue. At first the puzzled doctors guessed that she had influenza. But when her condition didn’t improve, the Xus returned to the ER, where Kate was diagnosed with Kawasaki disease and treated with intravenous immunoglobulin, antibodies that help boost immunity. In time she shook off the illness without suffering damage to her heart, making her one of the lucky ones.

Cut to a decade later: Ellen, needing a project for a high school science fair, recalled her sister’s illness. “It was a puzzle I wanted to solve,” says Ellen, now a student at Stanford. So she set out to do just that. Using data, she devised an algorithm that can identify the physical symptoms of Kawasaki disease from a photo. (It works similarly to apps that can identify birds and plants.) The app is expected to appear soon on the Kawasaki Disease Foundation’s website, kdfoundation.org.

As for Kate, Ellen says the little girl with the mysterious disease is now a thriving high school junior with dreams of becoming an environmental engineer.