I agree that it is extremely unlikely for a immune competent 13 month
old child to have a Candidal infection into the lungs. Even if he were
taking steroids. You can't make a diagnosis of a cause of pneumonia by
the x-ray.
If it were Candida, you would not expect nystatin, which works locally,
and not absorbed by the gut, to work on infection in the lung. I would
be extremely concerned about a Candidal infection in the lung, and would
treat aggressively with fluconazole--if it were Candida, which I doubt.
Probably much more likely viral.
Jack Newman, MD, FRCPC