Which viral infection is known to cause obstruction of the upper airway in children?

Croup is a viral infection that is particularly known for causing obstruction of the upper airway in children. It typically presents with a distinctive cough that is often described as barking, along with stridor and hoarseness. The condition is primarily caused by viruses, most commonly the parainfluenza virus, and leads to inflammation and swelling of the larynx and upper airway, thereby obstructing airflow.

In contrast, asthma is a chronic condition that affects the airways but does not typically start with an infectious cause. While it can lead to difficulties with breathing, it is characterized more by bronchoconstriction and inflammation in the lower airways rather than obstruction of the upper airway.

Bronchiolitis, predominantly caused by respiratory syncytial virus (RSV), affects the small airways (bronchioles) in infants and young children, leading to wheezing and respiratory distress. This condition primarily involves inflammation in the lower airways, rather than the upper airway.

Pneumonia is an infection of the lungs that leads to inflammation of the alveoli. While pneumonia can cause significant respiratory distress, it does not typically lead to obstruction of the upper airway, which is a key feature of croup.

Thus, croup's specific mechanisms