Runny Nose: Allergies, Colds & Other Causes

A runny nose is a common symptom that can be caused by a cold, the flu, allergies, sinusitis, or nasal irritation. It may feel like constant dripping or congestion and can occur on its own or with other symptoms.

Depending on the cause, a runny nose may be linked to sneezing, watery eyes, cough, facial pressure, or a low-grade fever. In some cases, it may also be related to nasal polyps, a deviated septum, pregnancy, acid reflux, or overuse of decongestant sprays.

Most cases of a runny nose are temporary, but symptoms that last more than a week may require medical evaluation. Treatment options vary and can include rest, fluids, saline rinses, antihistamines, nasal corticosteroids, or other medications based on the underlying cause.

Main causes

The main causes of a constant runny nose are:

1. Flu and colds

The flu and the common cold can cause a constant runny nose. They are caused by viral infections, such as influenza or rhinovirus, which can enter through the nose and lead to inflammation and irritation of the nasal lining.

According to the CDC, flu symptoms can include fever or chills, cough, sore throat, runny or stuffy nose, body aches, headaches, and fatigue. Common cold symptoms can include a runny or stuffy nose, cough, sneezing, sore throat, headache, mild body aches, and sometimes a low-grade fever.

This type of runny nose can take up to 10 days to go away and is usually not a cause for concern. It tends to resolve once the body is able to fight off the virus.

How to treat: To recover faster from the flu or a cold, rest, drink about 2 liters of water per day, eat a balanced diet, and avoid sudden temperature changes.

2. Respiratory allergies

Respiratory allergies, also called allergic rhinitis, is a very common cause of a constant runny nose. It is more common in the spring, when there are more allergens in the air, such as pollen, dust, or pet dander.

In these cases, the runny nose is usually accompanied by other symptoms such as watery eyes, frequent sneezing, and a feeling of pressure or heaviness around the nose.

How to treat: Avoid contact with the substance that triggered the allergy. If the cause is not clear, a healthcare provider may recommend antihistamines and decongestants to help relieve the runny nose and other allergy symptoms.

3. Sinusitis

Sinusitis is inflammation of the lining of the sinuses and facial cavities. It can be caused by bacteria, viruses, fungi, or allergies, and it may lead to a constant runny nose.

Along with a runny nose, other common sinusitis symptoms may include fever, headache, facial pressure, and pain near the eyes that gets worse when lying down or bending the head forward.

How to treat: Nasal rinses with saline solution are recommended, as well as nebulization with saline 3 times per day. Medications for sinusitis should be used according to your primary care provider or an ENT.

4. Rhinitis

Non-allergic rhinitis is inflammation of the nasal lining caused by pollution, smoke, strong odors, or temperature changes. It can create the sensation of a constant runny nose.

Even though the symptoms are very similar to an allergy (including sneezing and watery eyes), they are not caused by the immune system. Because of this, treatment needs to be different.

Directions: Nasal decongestants prescribed by a healthcare provider are commonly used. Nasal rinses may also be recommended to remove excess mucus.

5. Nasal polyps

A constant runny nose may happen due to nasal polyps, which are abnormal growths of tissue in the lining of the nose or sinuses. When they are large or grouped together, they can block airflow through the nose.

Nasal polyps are more common in people with respiratory problems that constantly irritate the nasal lining, such as sinusitis, allergic rhinitis, or asthma.

How to treat: Treatment is guided by an ENT, who may recommend medications such as nasal corticosteroids to reduce inflammation or irritation and ease symptoms. In some cases, surgery to remove the polyps may be recommended.

6. Deviated septum

A deviated septum is a change in the position of the nasal septum, which is the cartilage that separates the nostrils. This can alter airflow through the nose and make the nose feel dry.

Dryness can lead to increased mucus production as a response, which may result in a constant runny nose.

A deviated septum can be present from birth, but it can also be caused by a blow to the nose or local inflammation, for example.

How to treat: See an ENT specialist for an evaluation. Treatment may include surgery called septoplasty, depending on the severity.

7. Pregnancy

During pregnancy, it’s common for women to have a constant runny nose. This happens due to normal hormonal changes that can cause swelling of the nasal lining and increased mucus production.

In addition, increased blood volume during pregnancy may also contribute to swelling of the nasal lining and the development of a runny nose.

How to treat: A runny nose during pregnancy is temporary and usually improves after the baby is born. To relieve discomfort, you can do nasal rinses with saline solution or use saline nasal sprays, stay hydrated by drinking at least 8 glasses of water per day, and use a humidifier.

8. Overuse of decongestants

A constant runny nose may develop from overusing nasal decongestants in solution or spray form, such as naphazoline or pseudoephedrine, for example.

These medications narrow blood vessels in the nasal lining and can dry out the nose. In response, the nose may produce more mucus as a protective mechanism.

Because of this, excessive or prolonged use of nasal decongestants can worsen a runny nose. This reaction is known as rebound effect.

How to treat: Nasal decongestants should only be used under guidance from a healthcare provider and for the shortest time possible, usually 3 to 7 days, to help prevent nasal dryness.

9. Gastroesophageal reflux

Gastroesophageal reflux is the backflow of stomach contents toward the mouth. It can also affect the nasal lining, causing irritation and swelling, which may lead to nasal congestion and a constant runny nose.

How to treat: Treatment is guided by a primary care provider or gastroenterologist and may include the use of antacids, stomach-protecting medications, or medications that speed up stomach emptying. These options help reduce the return of stomach acid toward the mouth and relieve symptoms.