Anything that irritates the inside of the nose can cause a stuffy nose. Infections — such as colds, flu or sinusitis — and allergies often cause stuffy and runny noses. Irritants in the air, such as tobacco smoke, perfume, dust and car exhaust, also can cause these symptoms.

Some people have noses that are stuffy and run all the time without a known reason. This is called nonallergic rhinitis or vasomotor rhinitis.

A polyp, an object such as a small toy stuck in the nose, or a tumor might cause the nose to run from only one side. Sometimes migraine-like headaches can cause a runny nose.

Possible causes of nasal congestion include:

• Acute sinusitis
• Alcohol
• Allergies
• Chronic sinusitis
• Churg-Strauss syndrome
• Dry or cold air
• Common cold
• Decongestant nasal spray overuse
• Deviated septum
• Enlarged adenoids
• Food, especially spicy dishes
• Gastroesophageal reflux disease (GERD)
• Granulomatosis with polyangiitis (a condition that causes inflammation of the blood vessels)
• Hormonal changes
• Influenza (flu)
• Medications, such as those used to treat high blood pressure, erectile dysfunction, depression, seizures and other conditions
• Nasal polyps
• Nonallergic rhinitis
• Object in the nose
• Pregnancy
• Respiratory syncytial virus (RSV)
• Sleep apnea — a condition in which breathing stops and starts many times during sleep.
• Thyroid disorders.
• Tobacco smoke

For adults — See a health care provider if:

• You have symptoms for more than 10 days.
• You have a high fever.
• What's coming from your nose is yellow or green. You also have sinus pain or fever. This may be a sign of a bacterial infection.
• What's coming from your nose is bloody. Or your nose keeps running after a head injury.
• Your face hurts.

For children — See a health care provider if:

• Your child's symptoms don't get better or get worse.
• Your baby's stuffy nose causes problems with nursing or breathing.

Self-care

Until you see a care provider, try these simple steps to relieve symptoms:

• Avoid allergy causes.
• Try an allergy medicine you can get without a prescription. If you're also sneezing and your eyes are itching or watering, your nose might be running because of allergies. Be sure to follow the label instructions exactly.
• For babies, put several saline drops into one nostril. Then gently suction that nostril with a soft rubber-bulb syringe.

To relieve saliva that builds up at the back of the throat, also known as postnasal drip, try these measures:

• Avoid common irritants such as cigarette smoke and sudden humidity changes.
• Drink plenty of liquids, such as water, juice or broth. Liquids help break up congestion.
• Use nasal saline sprays or rinses.