Robbie’s mother calls a new pediatrician in a panic to report that her 5-year-old son has started a high-pitched, wheezing cough and cannot breathe. They have just moved from the Southwest to the Midwest, where they are renovating an old house. In the past, Robbie occasionally had slight coughs and tired easily, his mother says, but this episode is more alarming. The doctor says Robbie should be taken to a hospital emergency room immediately. What respiratory conditions does the doctor suspect? What may have triggered it?