In 2019, one of our kids got sick with something that was difficult to diagnose. After weeks of doctor visits, trips to the ER, and a hospital stay, we got a diagnosis of exclusion, which means they’d eliminated every possible disease and condition they thought it might have been and said, “It’s probably x.” The condition they diagnosed her as (probably) having is, itself, an umbrella diagnosis for kids who present with similar symptoms but who also don’t have a clear diagnosis of something else.