DD (18mo) has had a cold for a week or two. Nothing terribly awful - a bit of snot, a bit of a cough, a little wheezing at times treated with her inhaler. Nothing I felt needed the doctor.
Today she has a lot more snot, her cough is sounding quite productive and her temperature is up a bit (only 37.7 this morning, but usually 36.5). She's a little more whingy than normal, but not dreadfully sorry for herself.
So, do I assume this is simply another cold virus on top of what she already had, or might it be a chest infection (as her cough has changed and she now has a slight temp)?
How do I know the difference?