Is this normal? (constant colds)

[Boot]

I have looked after my friend's 3yo little girl for almost 2 years 2-3 days per week. She and my son are the same age and adore each other. This little girl has so many colds. It seems like she only gets a week or two break in between and they last forever. This current one has been going on for a month. She has lots of thick snot and a loose cough but otherwise seems happy and healthy. She eats and sleeps really well and is very easy going. I wonder if there is something going on like maybe asthma or allergies. Her mum doesn't seem too worried about it. My son never catches the colds from herby the way. What do you think? Is this normal?

[MamaPhD]

It sounds to me like she might have allergies. A friend's son had almost the same thing (except he was 5-6 years old), always a runny nose for like a year! They saw a specialist and found out he was allergic to some tree they have in their yard! Worth looking into!