A 9 month old infant presents with a 2–day history of fever, cough and breathlessness following an upper respiratory infection. She is febrile and has a respiratory rate of 80/min. Intercostal and subcostal retractions and extensive rhonchi on auscultation. A chest X–ray reveals a hyperinflated chest –
Bronchial asthma
Foreign body aspiration
Bacterial pneumonia
Bronchiolitis