What Causes Nasal Flaring?

Medically reviewed by George Krucik, MD, MBA

Nasal flaring occurs when your nostrils widen while breathing, and may be a sign that you’re having difficulty breathing. It’s most commonly seen in children and infants. In some cases, it can indicate respiratory distress. Read More

Nasal flaring occurs when your nostrils widen while breathing, and may be a sign that you’re having difficulty breathing. It’s most commonly seen in children and infants. In some cases, it can indicate respiratory distress.

What causes nasal flaring?

Nasal flaring can be caused by a number of conditions, ranging from temporary illness to long-term conditions and accidents. It may also be in response to vigorous exercise. A person breathing comfortably should not have nasal flaring.

Bacterial and viral infections

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

Asthma can be triggered by a number of stimuli, including:

  • animals
  • dust
  • mold
  • pollen


Epiglottitis is an inflammation of the tissue covering the trachea, or windpipe. It’s now rare because most people get immunized against the bacteria that cause it, H. influenzae type B, as children. At one point in time, epiglottitis was commonly seen in children aged 2 to 6, but 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’ll find it increasingly difficult to breathe, which can cause nasal flaring.

Exercise-induced nasal flaring

This is a temporary condition stimulated by the need to get more air into the lungs quickly in response to vigorous exercise such as running. This type of nasal flaring should subside in a few minutes and does not require any treatment.

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 oxygen isn’t being sufficiently pumped through your body.

What is the treatment for nasal flaring?

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

Your doctor will ask you a number of questions about your difficulty breathing, including:

  • when it began
  • if it’s getting better or worse
  • whether you have other symptoms, such as fatigue, drowsiness, or sweating

Your doctor will listen to your lungs and breathing to see if there’s 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 (CBC) to check for signs of infection
  • electrocardiogram (ECG) to assess how well 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 issues are severe, you may be given supplemental oxygen.

If an asthma diagnosis is made, your initial treatment will depend on the severity of your attack, and you may be referred to an asthma nurse to discuss your condition. Your ongoing treatment will depend on how well your symptoms are controlled. It’s a good idea to keep a diary of your asthma symptoms to identify potential triggers.

The most common treatment of asthma is inhaled corticosteroids to relieve inflammation and swelling of your airways. You may also have a quick-relief inhaler to be used 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 a nebulizer can take five minutes or more.

What is the outcome if nasal flaring is left untreated?

Nasal flaring is a symptom of breathing difficulties or an attempt to reduce airway resistance by widening the nasal opening. In most cases, these difficulties will worsen until the cause is diagnosed and treated. It can be serious, especially in children, and may require emergency medical treatment. Nasal flaring that is treated using medications or inhalers typically has no long-term consequences.

Medically reviewed by Deborah Weatherspoon, PhD, RN, CRNA on October 19, 2016Written by Kati Blake

12 possible conditions

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

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