Question

A person is dehydration and they start to bleed from their nose. But they're bleeding from only one nostril. Why?

Answer 1

The lining of your nose contains many tiny blood vessels that lie close to the surface and are easily damaged.

The two most common causes of nosebleeds are:

Dry air — when your nasal membranes dry out, they're more susceptible to bleeding and infections

Nose picking

Answer 2

Dryness of the nasal mucosa.
A dry nasal mucosa causes itching and people often scratch inside the nose due to this. It damages the delicate inner lining over the nostrils. Even if one does not scratch, the capillaries present there can rupture and bleed spontaneously due to excess dryness. This happens because the nasal mucosa is very thin and fragile. In conclusion, bleeding from one nostril is caused by too much Dry air — when your nasal membranes dry out, they're more susceptible to bleeding and infections.