When is a cough a reason to go and see my doctor?

What the evidence says

A cough alone usually doesn't need a doctor's visit if your child is otherwise playing, eating and breathing normally, since most coughs come from common cold viruses and settle within one to two weeks. For babies 3 months or younger, the advice is different: call your doctor at the very first sign of any illness, including cough, because young infants can get sick quickly and it can be hard to tell how unwell they really are.

See a doctor (same day or urgently) if your child is breathing fast, working hard to breathe (you can see the skin between the ribs pulling in, or flaring nostrils), has blue or pale lips, is unusually sleepy, floppy or hard to wake, or is very irritable and inconsolable. A barking cough with noisy breathing (croup) that isn't improving, or a cough so severe it causes vomiting, choking, or a whooping sound, also needs medical review.

Other reasons to book an appointment: a daytime cough lasting more than 10 days (or more than a week per Canadian guidance), thick nasal mucus lasting more than 10 to 14 days, fever over 38.9°C (102°F), ear pain, or a cough that keeps getting worse instead of better. Children with asthma, chronic lung disease, or a weakened immune system should be seen sooner if a new cough develops.

If you're ever unsure, most Canadian provinces have a free health line where a nurse can help you decide whether your child needs to be seen, and your doctor's office staff can usually help you triage over the phone too.