Your nose plays an important role in warming and humidifying the air you breathe.

"When we breathe in, our noses warm the air and add moisture as the air travels down into our lungs," says Melissa Schumacher, MD, an internal medicine physician at Northwestern Medicine. "Cold, dry air irritates your nasal lining, and as a result, your nasal glands produce excess mucus to keep the lining moist. That can cause those big, heavy drops that drip from your nostrils."

A study of 90 people visiting a ski-resort clinic found that 96% who were exposed to the cold had some degree of rhinorrhea, also known as "skier's nose." This type of runny nose usually produces clear, watery mucus.

"Typically, when it's related to cold temperatures and dry air, runny nose symptoms are brief and usually clear up when you warm up," says Dr. Schumacher.

How to Ease Symptoms

To help reduce symptoms, try to protect your nose from the cold when you're outdoors. "Wearing a scarf over your nose and mouth in cold weather can help because the air warms before it hits your nose," says Dr. Schumacher.

Other home remedies include:

• Drinking hot beverages
• Inhaling steam
• Using a saline nasal spray
• Adding humidity to a room

When Is a Runny Nose Something More?

If your runny nose continues once you're indoors or after you've warmed up, it could be more than just skier's nose. A persistent runny nose is one of the most typical symptoms of the common cold.

"We are more likely to pick up a cold in the winter because we spend more time inside, and germs survive longer in dry air. We're exposed to millions of germs every day that linger on doorknobs, keyboards and phones," says Dr. Schumacher.

Nasal mucus that is thick and yellowish green may indicate that you have a viral or bacterial infection. Other cold or flu-like symptoms accompanying a runny nose include fever, body aches, chills, nausea, sore throat, stuffiness, congestion, cough, trouble breathing, facial pain and fatigue. If the cause is a viral infection, such as a cold, a runny nose can last up to 10 to 14 days.

In some cases, a runny nose can lead to complications, such as postnasal drip, a sinus infection, ear pain or an ear infection. Your healthcare professional will determine if antibiotics or other medications are appropriate for treating the underlying cause.

If your symptoms worsen or your runny nose lasts longer than 10 days, call your doctor.

What Else Might Cause a Runny Nose?

Besides colds or infections, allergies are another common cause. Pollen, mold, mildew, pets and dust can trigger allergic reactions, and a runny nose usually continues as long as you're exposed. Pollen allergies, for example, can last six weeks during spring, summer or fall, depending on the source. Antihistamines can help.

You also might experience a runny nose when you:

• Cry
• Eat spicy foods
• Encounter irritants like smoke or strong odors

Other causes include frostbite, polyps, deviated septum, broken nose, stress, hormonal changes and side effects from medications.

Certain conditions can also cause a runny nose, such as:

• Hypothyroidism
• Autoimmune conditions that cause blood vessel inflammation
• Immunodeficiencies
• Cystic fibrosis
• Conditions that affect cerebrospinal fluid (CSF) flow

When to Call a Doctor

Seek medical attention if you experience:

• A runny nose that continues for 10 days or follows a head injury
• High or ongoing fever
• Discharge from one nostril
• Foul-smelling mucus
• Bloody mucus
• Difficulty breathing
• Facial swelling
• Blurred vision

How to Relieve a Runny Nose From a Cold

For adults, over-the-counter (OTC) cold medications can help ease symptoms. Here's what you need to know:

• Expectorants like guaifenesin are used to relieve chest congestion. They work by thinning the mucus in the air passages to make it easier to cough up the mucus and clear the airways.
• Decongestants reduce swelling of the nasal passages. They ease pressure and pain in your sinuses. They may help dry up a runny or stuffy nose.
• Nasal sprays can give relief, but be careful not to overuse them as they can make symptoms worse. 

Check with your healthcare professional to see what OTC cold medicines are appropriate for you. Always follow the instructions on the medication packaging.

How to Prevent a Runny Nose

To help prevent a runny nose due to a cold or flu, practice simple hygiene habits.

"Frequent handwashing, cleaning surfaces at home and work, sneezing or coughing into your elbow, and staying home when you're sick are key to avoid picking up — and spreading — germs," says Dr. Schumacher.

She recommends healthy lifestyle choices to boost your immune system:

• Eat nutritious foods, such as fresh fruits, vegetables, whole grains, nuts and seeds. These foods are rich in vitamins A, C, D and E and minerals like zinc that boost immune function.
• Be active regularly. Dr. Schumacher recommends at least 150 minutes of moderate-intensity aerobic activity per week.
• Get enough sleep (at least seven hours for most people).
• Manage your stress. Practice mindfulness and meditation to help reduce chronic stress.
• Avoid smoking and reduce or avoid alcohol intake. 
• Drink plenty of fluids, especially water.

"Focusing on good fluid intake, particularly hot fluids, along with optimal indoor humidity and nasal saline irrigation, can be effective in managing nasal symptoms during the winter," says Dr. Schumacher.