Which finding would necessitate immediate intervention in a child with respiratory illness?

Nasal flaring and retractions are significant indicators of respiratory distress in a child. These physical signs show that the child is struggling to breathe and requires immediate attention. Nasal flaring occurs as a response to increased respiratory effort, indicating that the child is trying to take in more air. Retractions, which are the visible sinking in of the skin above the collarbone or between the ribs during inhalation, signify that the muscles are working harder than usual to assist in breathing. This combination of findings typically suggests that there is a serious obstruction or difficulty in airflow, and without prompt intervention, the child's respiratory status could deteriorate rapidly.

In contrast, the other sets of symptoms do not typically require immediate intervention. Wheezing and coughing might indicate an ongoing respiratory issue but may not warrant urgent action unless accompanied by signs of significant distress. Fever and dehydration are serious concerns, particularly in young children, but they do not represent immediate respiratory dangers in the same way. Lastly, chest congestion and a sore throat are often symptoms of viral infections, which usually need evaluation but are less urgent unless they escalate to more severe respiratory problems.