The frontal chest x-ray shows right upper lobe collapse. There is increased density in the right upper lobe with upward displacement of the horizontal fissure; the right hilum is elevated.
In a paediatric patient with acute asthma presentation, the cause of the right upper lobe collapse is most likely due to mucus plugging.
In an asthmatic patient sick enough to be admitted to the hospital, a chest x-ray is required. A chest x-ray may show causes of exacerbation like pneumonia, collapse, or complications of asthma such as a pneumothorax or pneumomediastinum.
Reference: Grainger and Allison’s Diagnostic Radiology, A Textbook of Medical Imaging, 6th Edition.