A 15 month old baby girl presented to the emergency department with difficulty in breathing. Examination: she has intercostal recessions and a wheeze. Temperature normal. What is the most likely diagnosis?

The key is C. Bronchiolitis. [Asthma and bronchiolitis has similar sign symptoms. The difference is in pathology. In asthma there is bronchoconstriction but in bronchiolitis there is oedema of the airway wall. In infants and younger children bronchiolitis is commoner than asthma and it is seen that many of the children with bronhiolitis usually followed by asthma].