Inhalation of ammonia or other irritating chemicals sometimes causes nosebleeds, says Drugs.com. Other potential causes include respiratory illnesses, lack of humidity in the air, heavy drinking, a deviated septum, and medications or supplements that thin the blood. Trauma, such as blows to the face or forceful blowing of the noise, also causes nosebleeds. Medical conditions that cause nosebleeds include high blood pressure, hemophilia, thrombocytopenia and kidney failure.
Ammonia inhalation is serious and potentially life-threatening, reports the Agency for Toxic Substances and Disease Registry. Prolonged exposure in a space sometimes makes its presence difficult to detect because the sense of smell stops noticing it over time, a phenomenon called olfactory fatigue or adaptation. Severe cases of exposure present with burns to the respiratory tract, edema in the lungs and, in some cases, airway destruction that leads to death.
Nosebleeds that do not respond to simple first aid require immediate medical attention, notes Drugs.com. Most nosebleeds are not serious and resolve easily with minimal effort. Sitting up, pinching the nostrils shut just below the bridge of the nose and applying an ice pack to the bridge often stop nosebleeds quickly. Medical attention is necessary if these measures do not halt bleeding within 15 to 25 minutes, or if the bleeding is severe. If blood continues to ooze from the nose, it sometimes indicates a tumor or other blockage in the nose, especially among older smokers.