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What causes nasal flaring? 12 possible conditions

What Is Nasal Flaring?

Nasal flaring is when the nostrils widen while a person is breathing. It is a sign that the person is having difficulty breathing. It is most commonly seen in children and infants; in those cases nasal flaring can indicate respiratory distress.

What Causes Nasal Flaring?

Nasal flaring can be caused by a number of conditions, ranging from temporary illnesses to long-term conditions and even accidents.

Bacterial and Viral Infections

You may notice your nostrils flaring if you are suffering from a severe infection, such as influenza (flu). It is most commonly seen in people with serious respiratory conditions, such as pneumonia and bronchiolitis. Another common cause is croup, an inflammation of the larynx and trachea in children, which is associated with infection.


Nasal flaring is common in people suffering from acute asthma. It may occur along with other common asthma symptoms, such as wheezing, tightness of the chest, and shortness of breath. Asthma can be triggered by a number of stimuli, ranging from animals to dust, mold, and pollen.


Epiglottitis is inflammation of the tissue covering the trachea (windpipe). It is rare now because of childhood immunization against the bacteria that causes it (H.Influenzae type B). Epiglottitis was once most commonly seen in children aged two to six. It would be rare for an adult to develop the disease.

Airway Obstructions

If you have a blockage in the air passages around your nose, mouth, or throat, you will find it increasingly difficult to breathe.

Seeking Emergency Care

If you notice a child or infant with persistent nasal flaring, seek emergency medical attention.

You should also seek medical attention if you notice a blue tinge in your lips, skin, or nail beds. This indicates that sufficient oxygen is not being pumped through your body.

What Is the Treatment for Nasal Flaring?

Nasal flaring is usually an indication of a bigger problem and is not directly treated. It is not a symptom that can be treated at home.

Your doctor will ask you a number of questions about your difficulty breathing. This will include when it began, if it is getting better or worse, and whether you have other symptoms, such as fatigue, drowsiness, or sweating.

He or she will listen to your lungs and breathing sounds, and ascertain if there is any associated wheezing or if your breathing is unusually noisy.

Your doctor may order any or all of the following tests:

  • arterial blood gas to measure how much oxygen and carbon dioxide are in your blood
  • complete blood count to check for signs of infection
  • electrocardiogram (ECG) to assess how your heart is working
  • pulse oximetry to check the oxygen level in your blood
  • chest X-rays to look for signs of infection or damage

If your breathing problem is severe, you may be given supplemental oxygen.

If a diagnosis of asthma is made, your initial treatment will depend on the severity of your attack. You may be referred to an asthma nurse to discuss your condition. Your ongoing treatment will depend on how well your symptoms are managed. The most common treatment is inhaled corticosteroids to relieve inflammation and swelling of your airways. You may also have a quick-relief inhaler to use at the onset of an attack. Part of your therapy may include a nebulizer, which turns liquid medication into a fine mist that can be inhaled. Nebulizers are electric or battery powered; delivery of medication by nebulizer can take five minutes or more. It’s a good idea to keep a diary of your asthma symptoms to identify potential triggers.

What Is the Outcome if Nasal Flaring Is Left Untreated?

Nasal flaring is a symptom of breathing difficulties. In most cases, these difficulties will worsen until the cause is diagnosed and treated. Nasal flaring is unlikely to go away without treatment for the underlying cause.

Nasal flaring that is treated using medications or inhalers typically has no long-term consequences.

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See a list of possible causes in order from the most common to the least.


Acute Upper Airway Obstruction

An acute upper airway obstruction (UAO) is when a blockage occurs in your upper airway. The upper airway of your respiratory system consists of the trachea, voice box, and throat. A blockage in your airway could preven...

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Bronchiolitis is a viral respiratory condition that affects the smallest air passages in the lungs, the bronchioles. The job of these small, branching bronchioles is to control airflow in your lungs. When they becom...

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Croup is a viral condition that causes swelling around the vocal cords. It is characterized by breathing difficulties and a bad cough that sounds like a barking seal. Many of the viruses responsible for croup also caus...

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Pneumonia is an infection of the lungs caused by fungi, bacteria, or viruses. General symptoms include chest pain, fever, cough, and difficulty breathing.

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Pulmonary Edema

This condition is considered a medical emergency. Urgent care may be required.

Pulmonary edema is a condition in which the lungs fill with fluid. When this occurs, the body struggles to get enough oxygen, often resulting in breathlessness, coughing, excessive sweating, and bluish skin or lips.

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Neonatal Respiratory Distress Syndrome

A full-term pregnancy lasts 40 weeks. This gives the fetus time to grow. At 40 weeks, the organs are usually fully developed. If a baby is born too early, the lungs may not be fully developed, and they may not functio...

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RSV (Respiratory Syncytial Virus) Infection

Respiratory syncytial virus, or RSV, is a common virus that causes infections of the lungs and airways. Common symptoms include fever, wheezing, and bluish skin from oxygen deprivation.

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Transitory Tachypnea of Newborn

Amniotic fluid, contained within the amniotic sac, is very important to a developing baby. This fluid, which surrounds the unborn baby in the womb, acts as a cushion, protecting the baby from injury. It also keeps hi...

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Meconium Aspiration Syndrome

Meconium is dark-green fecal material that is produced in the intestines of a fetus before birth. After delivery, your newborn expels meconium stools for the first few days of life. Stress your baby experiences befor...

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Childhood Asthma

Asthma is a chronic condition in which the airways to your lungs become inflamed. The inflammation can make breathing difficult and painful. Childhood asthma affects almost nine million children in the United States...

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COPD Overview

Chronic obstructive pulmonary disease (COPD), is a lung condition usually caused by smoking. It makes breathing difficult, and wheezing, tightness in chest, and chest infections are common.

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Pneumothorax (Collapsed Lung)

Pneumothorax is a collapsed lung. This occurs when air becomes trapped in the space around the lungs. Along with a steady ache in the chest and shortness of breath, your skin or lips may turn blue.

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This feature is for informational purposes only and should not be used to diagnose.
Please consult a healthcare professional if you have health concerns.