If you have nonallergic rhinitis, you probably have symptoms that come and go year-round. You may have constant symptoms, or symptoms that last only a short time. Signs and symptoms of nonallergic rhinitis may include:

• Stuffy nose
• Runny nose
• Sneezing
• Mucus (phlegm) in the throat (postnasal drip)
• Cough

Nonallergic rhinitis doesn't usually cause itchy nose, eyes or throat — symptoms associated with allergies such as hay fever.

The exact cause of nonallergic rhinitis is unknown.

Experts do know that nonallergic rhinitis occurs when blood vessels in your nose expand and fill the nasal lining with blood and fluid. There are several possible causes, including the nerve endings in the nose being hyperresponsive, similar to the way the lungs react in asthma.

Whatever the trigger, the result is the same — swollen nasal membranes, congestion or excessive mucus.

There are many things known to trigger nonallergic rhinitis — some resulting in short-lived symptoms while others cause chronic problems. Nonallergic rhinitis triggers include:

• Environmental or occupational irritants. Dust, smog, secondhand smoke or strong odors, such as perfumes, can trigger nonallergic rhinitis. Chemical fumes, such as those you might be exposed to in certain occupations, also may be to blame.
• Weather changes. Temperature or humidity changes can trigger the membranes inside your nose to swell and cause a runny or stuffy nose.
• Infections. A common cause of nonallergic rhinitis is a viral infection — a cold or the flu, for example.
• Foods and beverages. Nonallergic rhinitis may occur when you eat, especially when eating hot or spicy foods. Drinking alcoholic beverages also may cause the membranes inside your nose to swell, leading to nasal congestion.
• Certain medications. Some medications can cause nonallergic rhinitis. These include aspirin, ibuprofen (Advil, Motrin IB, others), and high blood pressure (hypertension) medications, such as beta blockers.

Nonallergic rhinitis can also be triggered in some people by sedatives, antidepressants, oral contraceptives or drugs used to treat erectile dysfunction. Overuse of decongestant nasal sprays can cause a type of nonallergic rhinitis called rhinitis medicamentosa.

• Hormone changes. Hormonal changes due to pregnancy, menstruation, oral contraceptive use or other hormonal condition such as hypothyroidism may cause nonallergic rhinitis.
• Sleeping on your back, sleep apnea and acid reflux. Lying on your back at night while you sleep can cause nonallergic rhinitis, as can obstructive sleep apnea or acid reflux.

Factors that may increase your risk of nonallergic rhinitis include:

• Exposure to irritants. If you're exposed to smog, exhaust fumes or tobacco smoke — to name a few — you may be at increased risk of developing nonallergic rhinitis.
• Being older than age 20. Unlike allergic rhinitis, which usually occurs before age 20, often in childhood, nonallergic rhinitis occurs after age 20 in most people.
• Prolonged use of decongestant nasal drops or sprays. Using over-the-counter decongestant nasal drops or sprays (Afrin, Dristan, others) for more than a few days can actually cause more-severe nasal congestion when the decongestant wears off, often called rebound congestion.
• Being female. Due to hormonal changes, nasal congestion often gets worse during menstruation and pregnancy.
• Occupational exposure to fumes. In some cases nonallergic rhinitis is triggered by exposure to an airborne irritant in the workplace (occupational rhinitis). Some common triggers include construction materials, solvents, or other chemicals and fumes from decomposing organic material such as compost.
• Having certain health problems. A number of chronic health conditions can cause or worsen rhinitis, such as hypothyroidism and chronic fatigue syndrome.
• Stress. Emotional or physical stress may trigger nonallergic rhinitis in some people.

• Nasal polyps. These are soft, noncancerous (benign) growths that develop on the lining of your nose or sinuses due to chronic inflammation. Small polyps may not cause problems, but larger ones can block the airflow through your nose, making it difficult to breathe.
• Sinusitis. Prolonged nasal congestion due to nonallergic rhinitis may increase your chances of developing sinusitis — an infection or inflammation of the membrane that lines the sinuses.
• Middle ear infections. Increased fluid and nasal congestion may lead to middle ear infections.
• Interrupted daily activities. Nonallergic rhinitis can be disruptive. You may be less productive at work or school, and you may need to take time off because of symptom flares or doctor visits.