The child usually has a high fever and looks very ill.
The cough is deep and is similar to that caused by croup, but the usual croup treatments do not make the child's breathing easier.
Breathing becomes more difficult with time. The child makes a high-pitched sound sound when breathing in. This is called stridor.
The health care provider will perform a physical exam and listen to the lungs. The muscles between the ribs pull in as the child tries to breathe. This is called intercostal retractions.
Tests that may be done to diagnose this condition include: