Bleeding usually occurs from only one nostril. If the bleeding is heavy enough, the blood can fill up the nostril on the affected side and overflow within the nasopharynx (the area inside the nose where the two nostrils merge), spilling into the other nostril to cause bleeding from both sides. Blood can also drip back into the throat or down into the stomach, causing a person to spit or even vomit blood.
Signs of excessive blood loss include dizziness, light-headedness, confusion, and fainting. Excessive blood loss from nosebleeds is rare.
Additional bleeding from other parts of the body, such as bleeding gums when brushing teeth, blood in urine or bowel movements, or easy bruising may indicate an inability of the blood to clot. Additional bleeding or easy bruising can be a sign of a more significant medical problem.