Nasal flaring occurs when your nostrils widen while breathing. It 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.

Nasal flaring can be caused by a few conditions, ranging from temporary illnesses 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 have a severe infection such as the flu. It’s most commonly seen in people with serious respiratory conditions such as pneumonia and bronchiolitis.

Croup is another common cause of nasal flaring. In children, croup is an inflammation of the larynx and trachea and is associated with infection.


Nasal flaring is common in people with acute asthma. It may occur along with other common asthma symptoms, such as:

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


Epiglottitis is an inflammation of the tissue covering the trachea (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 most often affected children ages 2 to 6 years old, 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.

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.

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

Your healthcare provider will ask you 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:

If your breathing issues are severe, you may be given supplemental oxygen.

If your healthcare provider diagnoses you with asthma, your initial treatment will depend on the severity of your attack. You may also be referred to an asthma nurse to discuss your condition.

Your ongoing treatment will depend on how well your symptoms are managed. It’s a good idea to keep a diary of your asthma symptoms to identify potential triggers.

Inhaled corticosteroids are the most common asthma treatment to relieve inflammation and swelling of your airways. Your healthcare provider may also prescribe 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. A nebulizer can take 5 minutes or more to deliver medication.

Nasal flaring is a symptom of breathing difficulties or an attempt to widen the nasal opening to reduce airway resistance. In most cases, these difficulties will worsen until the cause is diagnosed and treated.

Nasal flaring can be serious, especially in children, and may require emergency medical treatment. Nasal flaring that’s treated using medications or inhalers typically has no long-term consequences.