Nosebleed, causes of: The nose is a part of the body that is very rich in blood vessels (vascular) and is situated in a vulnerable position on the face. As a result, any trauma to the face can cause bleeding which may be profuse. Nosebleeds can occur spontaneously when the nasal membranes dry out, crust, and crack, as is common in dry climates, or during the winter months when the air is dry and warm from household heaters. People are more susceptible if they are taking medications which prevent normal blood clotting (warfarin or other "blood thinner", aspirin, non-steroidal anti-inflammatory medication, or antiplatelet medications such as clopidogrel). Other predisposing factors include infection, trauma, allergic and non-allergic rhinitis, hypertension., alcohol abuse and inherited bleeding problems.