Which of the following is a typical sign of croup?

A barking cough is a hallmark sign of croup, which is typically caused by viral infections in young children. This distinctive cough resembles the sound of a seal and is accompanied by stridor, which is a high-pitched wheezing sound that occurs when the child breathes in. These features result from inflammation in the upper airways, particularly in the larynx and trachea, leading to the characteristic symptoms of croup.

While high fever can be associated with infections, it is not specifically indicative of croup, as temperatures can vary widely among those infected. Chest pain does not typically present with croup and is more often seen in respiratory conditions that affect the lower airways. Loss of appetite can occur due to various infections or illnesses in children, but it is not a defining characteristic of croup. Thus, the identifying feature that stands out in a case of croup is indeed the barking cough.