re especially likely to get a nosebleed when you have a cold, sinus infection, or allergies, or when the membranes inside your nose dry out, as they do in cold
weather, air-conditioned rooms, airline cabins
, and other dry environments. Trauma and certain medical conditions, such as high blood pressure or a clotting disorder, may cause nosebleeds as well.
How can I stop a nosebleed?