DD (nearly 3) has had a cough for 3 weeks now. The start of it coincided with a cold and conjunctivitis, so I wasn't worried. It's really phlegmy now though. She's not at all bothered by it and it doesn't keep her awake (coughs all night but sleeps through it). She's just coughed constantly through her tea.
I'm not usually worried about this sort of thing, but wonder if it needs to be checked out?