The croup cough has a distinct barking sound alongside various other croup symptoms. Learn more about croup cough and when to seek medical attention. What is Croup? Croup is a respiratory condition that primarily affects the windpipe (trachea), the airways to the lungs (bronchi), and the voice box (larynx). This area is called the laryngotracheobronchial tree. These areas become inflamed and swollen, which narrows the airways and leads to the distinctive symptoms associated with the ...