What could cause six cases of pneumonia and several other respiratory illnesses in a 5 year old?

See expert MD now.: Children with multiple pneumonias, in my opinion as a family physician with 30+ years in practice, should have evaluations done by the following specialists: immunologist, allergist, and if available, pediatric pulmonologist. At worst, cystic fibrosis needs to be considered. Common causes would be gastroesophageal reflux with resulting aspiration pneumonias, immune problems, and food allergies.

Depends: There is no single common cause of recurrent episodes of pneumonia. A patient history, physical exam and diagnostic tests will need to be conducted in order to determine the specific underlying cause of the recurrent respiratory infections. Check out http://tulsapedsresidency.Net/wards/pulm/recrntpneumonia.Pdf for more information.

Could it be asthma?: I agree with my colleagues' answers that this needs further evaluation by a pediatrician. Problems with the immune system, abnormal anatomy, and even cystic fibrosis can present with recurrent pneumonias. In my experience though, many times a child with asthma presents with multiple episodes of respiratory infections including so-called "asthmonia" recurrent pneumonias related to asthma.