The nose is a mucus factory, producing approximately one quart of mucus each day. This keeps germs, dirt and pollen from getting into the lungs because they are stopped in the nose. Sometimes the mucus becomes more fluid and begins to run out of the nose. There are many reasons this can happen, from the mundane allergy to less common disease-related side effects. Treatment for a runny nose will always be related to the reason it is happening.
Allergies
Individuals can have allergic reactions to a variety of different protein allergens. According to Mayo Clinic physicians, allergens that result in a runny nose can be related to latex, dust mite, milk, mold, peanuts, pets, shellfish, soy and wheat. Pollen and hay fever allergies can also cause a hyperactive response in the nose and result in a runny nose, reports the Mayo Clinic.
Influenza
The common cold virus attacks the mucus membranes in the back of the nose, causing extra watering and mucus production. In his education material for patients and families, board certified pediatrician Dr. Vinay N. Reddy explains that the influenza virus is spread through droplets that are sprayed out each time an infected person coughs or sneezes.
Other people become infected by breathing in those droplets, or carry them to their nose by touching an infected object and then touching their nose. The extra production of mucus results in a runny nose.
Cocaine Addiction
Individuals who abuse cocaine are subject to chronic runny noses and nose bleeds, according to the National Institute on Drug Abuse. Cocaine has a variety of effects on the body, such as constricted blood vessels, dilated pupils or increased body temperature.
When an addict introduces cocaine to the body through the nasal passages, it leads to loss of smell, nosebleeds, problems with swallowing and a chronically runny nose, according to the National Institute on Drug Abuse.
Cold Temperature
When outside on a cold day, the body attempts to warm the air before it reaches the lungs. To do this, the blood vessels in the nose will dilate, increasing the amount of warm blood the air passes over before reaching the lungs. Kids Health explains that all of this extra blood flow increases the mucus production in the nose and results in a runny nose.
Medications
High blood pressure medications and overuse of decongestant nasal sprays are just two of the medications that can cause a runny nose, notes the Mayo Clinic. Medications that affect the dilation of blood vessels throughout the body will also affect the blood flow to the mucus membranes in the nose, increasing production of mucus and resulting in a runny nose.
Medical Conditions
A runny nose can also be the symptom of another significant underlying medical condition. Mayo Clinic physicians list cluster headaches, migraines, bronchiolitis and acute sinusitis as conditions that can cause increased mucus production.
Some of the less common medical conditions that cause runny noses include Churg-Straus, DiGeorge or Wegener's. Churg-Strauss syndrome is an inflammation of the blood vessels that can restrict flow to vital organs and will cause a runny nose.
DiGeorge Syndrome is a genetic disorder that causes runny noses, poor immune system function, heart defects and cleft lip and palate. Wegener's granulomatosis also affects the dilation of blood vessels, targeting the kidneys, lungs and upper respiratory tract.
